Auxiliary Interstate Highways (also called three-digit Interstate Highways) are a supplemental subset of the freeways within the Interstate Highway System of the United States. Auxiliary routes are generally classified as spur routes, which connect to the parent route at one end, bypasses, which connect to the parent route at both ends, or beltways, which form a complete circle intersecting the parent route at two locations. There are 323 auxiliary Interstates in the United States. There are some routes which connect to the parent route at one end, but connect to another route at the other end; some states treat these as spurs while others treat them as bypasses. Similar to the mainline Interstate Highways, these highways also meet all Interstate Highway standards (with rare exceptions), and they receive the same percentage of federal funding (90%).
|Dwight D. Eisenhower National System of Interstate and Defense Highways|
|Formed||June 29, 1956|
|Interstates||Interstate X (I-X)|
The shorter auxiliary routes branch off main routes and are numbered based on the number of the parent route. All of the supplement routes for Interstate 95 (I-95) are designated with a three-digit number ending in "95" in the form I-x95. While some exceptions do exist, generally spur routes are numbered with an odd hundreds digit (such as I-395), while bypasses and beltways are numbered with an even hundreds digit (such as I-695). Because longer Interstates may have many such supplemental routes, the numbers can repeat from state to state along their route, but they will not repeat within a state.
There are only three states that do not have any auxiliary Interstate Highways: Alaska, Arizona, and New Mexico. North Dakota has an auxiliary route, but it is unsigned, and Wyoming's does not meet Interstate Highway standards.
Terminology and guidelinesEdit
The basic tenets of the auxiliary Interstates are divided into three branches: spur, loop, and bypass routes. Each one signifies a different characteristic of the auxiliary route.
The first digit of the three digits usually determines whether a route is a bypass, spur, or beltway. The last two digits are derived from the main Interstate Highway. For instance, I-515 contains an odd number in the first digit (5), and this indicates that this freeway is a spur. The last two digits signify the highway's origin. In this case, the "15" in I-515 shows that it is a supplement to I-15.
Numerous exceptions to the standard numbering guidelines exist in many places. This can be for a number of reasons. In some cases, original routes were changed, extended, or abandoned, leaving discrepancies in the system. In other cases, it may not be possible to use the proper number because the limited set of available numbers has been exhausted, causing a "non-standard" number to be used.
A spur route's number usually has an odd number for its first digit. It is usually one of the following:
- It may serve another section of a city or metropolitan area not served by the main freeway (most often the central business district), terminating at a regular city street/avenue or at a substandard freeway, such as I-185 in Columbus, Georgia.
- It may represent the first portion of a contemplated extended freeway, one that downgrades to below Interstate standards with plans to upgrade it later on. An example is I-540 in Arkansas.
- It may connect two unrelated Interstate highways—as I-390 in New York State and I-355 in Illinois do.
- Note that states differ on their interpretation of the numbering convention in this case. In the I-390 example above, the route has both ends at Interstates, but not at the same Interstate on both ends, and is assigned an odd first digit. Another example is I-275 in Tennessee: it is a connector between I-40 and I-75 (a similar case of having both ends at Interstates but not at the same Interstate) and is assigned an even first digit.
- Note that this may even vary within the same state. For example, in Michigan, both I-196 and I-696 intersect I-96 at one end and I-94 at the other end.
- I-110 in California links I-10 with the Port of Los Angeles. This freeway was built before Interstate Highways as the Harbor Freeway. Later, it was adopted into the Interstate Highway System.
- I-180 in North-Central Pennsylvania connects Williamsport and Lycoming County with I-80 in Milton, which does not actually enter Lycoming County. I-180 also serves as a connection to those traveling to New York and I-86 via U.S. Route 15 and the Future I-99 Corridor at its western terminus.
- I-190 in New York connects the cities of Niagara Falls and Buffalo with I-90.
Sometimes, a three-digit Interstate Highway branches off from another three-digit Interstate Highway. These spurs do not connect directly with their parent highways, but are associated with them via the three-digit highways they do intersect with.
- I-380 in Northern California is located at the San Francisco Bay Area. This highway begins at I-280, and it connects with US 101 and San Francisco International Airport.
- I-190 in Massachusetts branches off from I-290 near Worcester.
- I-795 in Baltimore County, Maryland branches off from I-695.
A bypass route may traverse around a city, or may run through it with the mainline bypassing. In a typical 3-digit Interstate Highway, bypasses usually have both its two termini junctioned with another Interstate highway. Bypass routes are preceded by an even number in the first digit.
- I-220 in Louisiana serves as a bypass of downtown Shreveport.
- I-440 forms a loop around the south side of Nashville.
- I-890 travels through downtown Schenectady, which I-90 avoids.
In the case of an auxiliary Interstate highway which has both ends at Interstates but not the same Interstate, some states treat these as bypasses while others treat these as spurs — see Spur route above.
A beltway (also known as a loop route) completely surrounds a metropolitan city, and it is often connected with multiple junctions to other routes. Unlike other auxiliary Interstate Highways (and by extension, all primary Interstate Highways), beltways do not have termini; however, they have a place where the highway mileage resets to zero. Beltways are also preceded by an even number in the first digit.
Some examples of beltways include:
- I-275 in Ohio, Kentucky and Indiana encircles the city of Cincinnati.
- I-465 in Indiana encircles the city of Indianapolis.
- I-495 in Maryland and Virginia encircles the city of Washington, D.C. and is referred to as "The Capital Beltway".
- Note: this table sorts the route numbers by parent highway.
|Number||Length (mi)||Length (km)||Southern or western terminus||Northern or eastern terminus||Formed||Removed||Notes|
|H-201||4.10||6.60||H-1 in Halawa, HI||H-1 in Honolulu, HI||2004||current||Signed as Route 78 until 2004|
|I-105||17.32||27.87||SR 1 in El Segundo, CA||I-605 in Norwalk, CA||1963||current||Replaced segments of SR 42|
|I-205||12.97||20.87||I-580 near Tracy, CA||I-5 near Tracy, CA||1970||current|
|I-305||6.00||9.66||I-80 in West Sacramento, CA||I-80 Bus/US 50/SR 99 in Sacramento, CA||1981||current||Unsigned|
|I-405||72.15||116.11||I-5 in Irvine, CA||I-5 in Mission Hills, CA||1964||current|
|I-505||32.98||53.08||I-80 in Vacaville, CA||I-5 in Dunnigan, CA||1977||current||Originally part of I-5W|
|I-605||27.40||44.10||I-405 in Seal Beach, CA||I-210 in Irwindale, CA||1964||current|
|I-805||28.02||45.09||I-5 in San Ysidro, CA||I-5 in Sorrento Valley, CA||1959||current|
|I-905||8.96||14.42||I-5 in San Ysidro, CA||Fed. 2 at the United States-Mexico border in Otay Mesa, CA||proposed||—||Currently SR 905, proposed to be signed as an Interstate|
|I-105||3.49||5.62||OR 99 in Eugene, OR||I-5 in Springfield, OR||1958||current|
|I-305||—||—||Pine Street in Salem, OR||I-5 in Keizer, OR||1957||1976||Canceled|
|I-405||3.53||5.68||I-5 in Portland, OR||I-5 in Portland, OR||1958||current|
|I-505||3.17||5.10||US 30 in Portland, OR||I-405 in Portland, OR||1969||1979||Canceled|
|I-205||36.64||58.97||I-5 in Tualatin, OR||I-5 in Salmon Creek, WA||1958||current|
|I-405||30.30||48.76||I-5/SR 518 in Tukwila, WA||I-5/SR 525 in Lynnwood, WA||1957||current|
|I-605||—||—||WA 99 in Federal Way, WA||I-5 in Everett, WA||—||—||Never built, was planned to bypass Seattle, WA|
|I-705||1.50||2.41||I-5/SR 7 in Tacoma, WA||Schuster Parkway in Tacoma||1978||current|
|I-210||4.9||7.9||I-10 in Mobile, AL (original southern terminus)||I-65 in Prichard, AL||—||—||Currently I-165, the route number was decommissioned because it had no connection to I-10|
|I-410||—||—||I-10/I-17 in Phoenix, AZ||I-10 in Phoenix, AZ||—||—||Now part of I-10 in Phoenix, AZ|
|I-510||—||—||I-10/SR 51 in Phoenix, AZ||SR 101 in Phoenix, AZ||—||—||Currently designated as SR 51 (Piestewa Freeway)|
|I-710||—||—||I-10 in Tucson, AZ||North Campbell Avenue/East 6th Street in Tucson, AZ||—||—||Mostly never built freeway that was to connect to University of Arizona campus from I-10|
|I-110||20.43||32.88||SR 47 in San Pedro, CA||I-10/SR 110 in Los Angeles, CA||1978||current||Originally part of US 6, then signed as SR 11|
|I-210||48.72||78.41||I-5 in Sylmar, CA||SR 57/SR 210 in Glendora, CA||1964||current||Segment from SR 57 east to I-10 is still signed as SR 210, formerly SR 30 prior to 2007.|
|I-710||19.66||31.64||Terminal Island in Long Beach, CA||Valley Boulevard in Alhambra, CA||1983||current||Originally signed as SR 7|
|I-110||6.94||11.17||US 98 Bus. near Pensacola, FL||I-10 near Pensacola, FL||1969||current|
|I-110||8.89||14.31||I-10 in Baton Rouge, LA||US 61 in Baton Rouge, LA||1964||current|
|I-210||12.40||19.96||I-10 west of Lake Charles, LA||I-10 east of Lake Charles, LA||1964||current|
|I-310||11.25||18.11||US 90/LA 3127 in Boutte, LA||I-10 west of Kenner, LA||1983||current|
|I-310||2.70||4.35||US 90 Bus. in New Orleans, LA||I-10 in New Orleans, LA||1964||1969||Canceled Vieux Carré Riverfront Expressway|
|I-410||1.90||3.06||LA 67 in Baton Rouge, LA||I-10 in Baton Rouge, LA||1961||1964||Renumbered as I-110|
|I-410||48.5||78.1||I-10 west of New Orleans, LA||I-10 in New Orleans, LA||1969||1977||Canceled southern bypass of New Orleans|
|I-510||3.04||4.89||LA 47 in New Orleans, LA||I-10/LA 47 in New Orleans, LA||1992||current|
|I-610||4.52||7.27||I-10 at Metairie–New Orleans, LA line||I-10 in New Orleans, LA||1965||current|
|I-910||9.70||15.61||US 90 Bus. in Marrero, LA||I-10/US 90 Bus. in New Orleans, LA||1999||current||Signed as part of US 90 Bus. and Future I-49|
|I-110||4.10||6.60||US 90 in Biloxi, MS||I-10 in D'Iberville, MS||1988||current|
|I-310||—||—||US 90 near the Port of Gulfport, MS||I-10 in Gulfport, MS||proposed||—||Future spur into Gulfport, MS|
|I-110||0.92||1.48||Av Abraham Lincoln at the United States-Mexico border in El Paso, TX||I-10 in El Paso, TX||1967||current|
|I-410||49.49||79.65||Beltway around San Antonio, TX||1959||current|
|I-610||37.97||61.11||Beltway around Houston, TX||1975||current|
|I-215||54.50||87.71||I-15 in Murrieta, CA||I-15 in Devore, CA||1982||current||Originally signed as I-15E, then SR 215|
|I-115||1.19||1.92||I-15/I-90 in Butte, MT||Iron Street in Butte, MT||1971||current|
|I-315||0.83||1.34||I-15 in Great Falls, MT||I-15 Bus/US 89 in Great Falls, MT||1960||current||Unsigned|
|I-215||11.10||17.86||I-15/Clark County Route 215 in Enterprise, NV||I-515/US 93/SR 564 in Henderson, NV||1996||current|
|I-515||20.54||33.06||US 93/US 95 in Henderson, NV||I-15/US 93/US 95 in Las Vegas, NV||1976||current||Not signed until 1994, this route is entirely concurrent with US 93/US 95|
|I-215||29.02||46.70||I-80 in Salt Lake City, UT||I-15 in North Salt Lake, UT||1963||current|
|I-415||2.39||3.85||I-80 in Salt Lake City, UT||4430 S in Holladay, UT||1965||1969||Designation was scrapped to provide a single route number 215 for the entire route.|
|I-516||6.49||10.44||SR 21/SR 204 in Savannah, GA||SR 21 in Garden City, GA||1985||current|
|I-420||5.40||8.69||I-285 in College Park, GA||I-20 in Atlanta, GA||1983||1986||Never built, was planned to bypass Atlanta, GA|
|I-520||23.34||37.56||I-20 in Augusta, GA||I-20 in North Augusta, SC||1980||current|
|I-220||17.62||28.36||I-20/LA 3132 in Shreveport, LA||I-20 in Bossier City, LA||1979||current|
|I-420||10.20||16.42||I-20 in West Monroe, LA||I-20 in Monroe, LA||1957||1964||Canceled bypass of Monroe|
|I-220||12.01||19.33||I-20 in Jackson, MS||I-55 in Ridgeland, MS||1981||current|
|I-820||35.17||56.60||I-20 in Fort Worth, TX||I-20/US 287 in Fort Worth, TX||1959||current|
|I-222||—||—||I-22 in Graysville, AL||I-422 in Brookside, AL||proposed||—||Proposed connector between I-422 and I-22 due to the inability to make a direct connection between the two routes.|
|I-422||—||—||I-20/I-59/I-459/US 11 in Bessemer, AL||I-59 in Argo, AL||proposed||—||Currently under construction; will only be indirectly connected to I-22 via I-422.|
|I-124||1.97||3.17||I-24 in Chattanooga, TN||US 27 in Chattanooga, TN||1960||current||Unsigned|
|I-225||12.00||19.31||I-25 in Denver, CO||I-70 in Aurora, CO||1976||current|
|I-425||5.31||8.55||I-25/US 36 at Welby, CO||I-70/US 36 at Denver, CO||—||1959||Renumbered as I-270 by AASHTO|
|I-126||3.68||5.92||I-26 in Columbia, SC||US 21/US 76/US 176/US 321 in Columbia, SC||1961||current|
|I-326||5.24||8.43||I-26 in Cayce, SC||SC 48 in Columbia, SC||1976||1995||Now part of I-77, formerly unsigned|
|I-526||19.26||31.00||US 17 in Charleston, SC||I-526 Bus./US 17 in Mount Pleasant, SC||1989||current|
|I-129||3.48||5.60||US 20/US 75/US 77 in South Sioux City, NE||I-29/US 20/US 75 in Sioux City, IA||1976||current|
|I-229||14.97||24.09||I-29 in St. Joseph, MO||I-29/US 59/US 71 in St. Joseph, MO||1986||current|
|I-229||11.33||18.23||I-29 in Sioux Falls, SD||I-90 near Sioux Falls, SD||1966||current|
|I-130||5||8.0||I-30/I-49 in Texarkana, AR||US 59/US 71 near Texarkana, AR||2000||2014||Was given a future designation during its existence due to not being upgraded to Interstate Highway standards; freeway became part of I-49 once completed|
|I-430||12.93||20.81||I-30/US 67 in Little Rock, AR||I-40/US 65 in Little Rock, AR||1980||current|
|I-530||46.65||75.08||US 65 in Pine Bluff, AR||I-30/I-440 in Little Rock, AR||1999||current|
|I-630||7.40||11.91||I-430 near Little Rock, AR||I-30 in Little Rock, AR||1985||current|
|I-235||13.78||22.18||I-35/I-80 in West Des Moines, IA||I-35/I-80 near Des Moines, IA||1961||current|
|I-135||95.74||154.08||Kansas Turnpike/I-35 in Wichita, KS||I-70/US 81 in Salina, KS||1976||current|
|I-235||16.52||26.59||I-135/US 81 in Wichita, KS||I-135/US 81/K-15/K-254 in Wichita, KS||1965||current|
|I-335||50.13||80.68||I-35/Kansas Turnpike/US 50 in Emporia, KS||I-470/Kansas Turnpike in Topeka, KS||1987||current|
|I-435||80.81||130.05||Beltway around Kansas City, KS, and Kansas City, MO||1965||current|
|I-635||8.90||14.32||I-35 in Overland Park, KS||I-29/US 71 in Kansas City, MO||1968||current|
|I-335||2.74||4.41||I-94 in Minneapolis, MN||I-35W in Minneapolis, MN||1964||1978||Canceled|
|I-535||2.78||4.47||I-35/US 53 in Duluth, MN||US 53/WIS 35 in Superior, WI||1971||current|
|I-235||5.36||8.63||I-35/I-40 in Oklahoma City, OK||I-44 in Oklahoma City, OK||1989||current|
|I-635||37.00||59.55||SH 121 in Grapevine, TX||I-20 in Balch Springs, TX||1959||current|
|I-238||2.23||3.59||I-880 in San Leandro, CA||I-580/SR 238 in Castro Valley, CA||1983||current||Considered an auxiliary route of I-80 in California; there is no I-38|
|I-440||9.96||16.03||I-30/I-530 near Little Rock, AR||I-40/AR 440 near Little Rock, AR||2003||current|
|I-540||15.87||25.54||US 271/AR 253 near Fort Smith, AR||I-40 in Van Buren, AR||1965||current|
|I-140||6.79||10.93||US 17 near Winnabow, NC||I-40/US 17 in Wilmington, NC||2008||current|
|I-240||9.54||15.35||I-26/I-40/US 74 near Asheville, NC||I-40/US 74A in Asheville, NC||1980||current|
|I-440||16.77||26.99||I-40/US 1/US 64 near Cary, NC||I-40 near Raleigh, NC||1991||current|
|I-540||25.84||41.59||I-40 near Durham, NC||I-87/US 64/US 264 near Knightdale, NC||1997||current|
|I-840||5.77||9.29||I-40/I-73/US 421 in Greensboro, NC||I-40/I-85/I-785/I-85 Bus. in Greensboro, NC||2011||current|
|I-240||16.22||26.10||I-44/US 62 in Oklahoma City, OK||I-40/US 270 in Oklahoma City, OK||1965||current||Designation planned to be extended to make a complete beltway around Oklahoma City.|
|I-440||9.96||16.03||I-40/I-240 near Oklahoma City, OK||I-35 in Oklahoma City, OK||—||1975||Now part of I-44|
|I-140||11.17||17.98||I-40 near Farragut, TN||US 129 near Alcoa, TN||1987||current|
|I-240||19.27||31.01||I-40 in Memphis, TN||I-40 in Memphis, TN||1970||current|
|I-440||7.64||12.30||I-40 in Nashville, TN||I-24 in Nashville, TN||1987||current|
|I-640||7.03||11.31||I-40 in Knoxville, TN||I-40 in Knoxville, TN||1982||current|
|I-840||77.28||124.37||I-40 near Dickson, TN||I-40 near Lebanon, TN||2016||current||Originally designated SR 840 until completion|
|I-244||15.75||25.35||I-44 in Tulsa, OK||I-44 in Tulsa, OK||1970||current|
|I-444||2.51||4.04||I-244 in Tulsa, OK||I-244 in Tulsa, OK||1970||current||Unsigned|
|I-345||1.40||2.25||I-30/I-45 in Dallas, TX||US 75 in Dallas, TX||1973||current||Unsigned|
|I-555||49.80||80.15||I-55 in Turrell, AR||AR 91 in Jonesboro, AR||2016||current|
|I-155||32.13||51.71||I-74 in Morton, IL||I-55 in Lincoln, IL||1992||current|
|I-255||30.82||49.60||I-55/I-270 in Mehlville, MO||I-270/IL 255 in Pontoon Beach, IL||1986||current|
|I-355||32.51||52.32||I-80 in New Lenox, IL||I-290 in Itasca, IL||1989||current|
|I-155||15.93||25.64||I-55 near Hayti, MO||US 51 at Dyersburg, TN||1980||current|
|I-255||—||—||I-55/I-240 in Memphis, TN||I-40 in Memphis, TN||—||—||Now part of I-55 and I-240|
|I-359||2.30||3.70||I-20/I-59 in southern Tuscaloosa, AL||15th Street in downtown Tuscaloosa, AL||1983||current|
|I-459||32.80||52.79||I-20/I-59 in Bessemer, AL||I-59 in Trussville, AL||1984||current|
|I-759||4.50||7.24||I-59 in Attalla, AL||US 411/SR 759 in Gadsden, AL||1986||current|
|I-164||21.39||34.42||US 41/Veterans Memorial Parkway in Evansville, IN||I-69 in Evansville, IN||1990||2014||Decommissioned; now part of I-69|
|I-264||22.93||36.90||I-64 in Louisville, KY||I-71 in Louisville, KY||1956||current|
|I-264||25.07||40.35||I-64/I-664 in Chesapeake, VA||Parks Ave in Virginia Beach, VA||1960||current|
|I-464||4.71||7.58||I-64 in Chesapeake, VA||I-264 in Norfolk, VA||1960||current|
|I-564||3.03||4.88||SR 337||I-64 in Norfolk, VA||1970||current|
|I-664||20.21||32.52||I-64/I-264 in Norfolk, VA||I-64 in Hampton, VA||1971||current|
|I-165||4.90||7.89||US 43 in Mobile, AL||I-65 in Mobile, AL||1994||current|
|I-565||21.40||34.44||I-65/US 72/SR 20 in Decatur, AL||US 72 in Huntsville, AL||1991||current|
|I-265||2||3.2||I-40 in Nashville, TN||I-65 in Nashville, TN||—||2000||Now part of I-65|
|I-165||69.684||112.146||I-65 in Bowling Green, KY||US 60/US 231 in Owensboro, KY||2019||current||Replaced the William H. Natcher Parkway|
|I-265||24.48||39.40||I-65/I-265/KY 841 in Heritage Creek, KY||I-71/KY 841 in Prospect, KY||1977||current||Connected with I-265 in Indiana on December 18, 2016, with the completion of the East End Bridge|
|I-365||92.313||148.563||I-65 near Park City, KY||US 27 in Cumberland, KY||proposed||—||Future designation along the Cumberland Parkway|
|I-165||2.70||4.35||I-65/I-70 in Indianapolis, IN||38th Street in Indianapolis, IN||1978||1981||Was to be a spur linking from I-65/70 to 38th Street entirely with Indianapolis|
|I-265||6.73||10.83||I-64 in New Albany, IN||SR 62/I-265 in Clarksville, IN||1977||current||Connected with I-265 in Kentucky on December 18, 2016, with the completion of the East End Bridge|
|I-465||52.79||84.96||Beltway around Indianapolis||1970||current|
|I-865||4.72||7.60||I-65 near Indianapolis, IN||I-465 near Indianapolis||2002||current|
|I-266||1.79||2.88||—||—||—||1972||Proposed loop route of I-66 between the District, and Arlington County; if built, would have been the only auxiliary route of I-66; canceled in the face of community opposition during Washington's freeway revolts|
|I-169||34.27||55.15||I-24 near Hopkinsville, KY||I-69 in Nortonville, KY||2017||current||New designation along the former Pennyrile Parkway|
|I-369||23.441||37.725||I-69/Pennyrile Parkway in Henderson, KY||US 60 in Owensboro, KY||proposed||—||Proposed for designation along Audubon Parkway once upgraded to Interstate standards|
|I-569||38.446||61.873||I-69/I-169 in Nortonville, KY||I-165 in Beaver Dam, KY||proposed||—||Future designation for the western part of Western Kentucky Parkway once upgraded to Interstate standards|
|I-269||45.19||72.73||I-55/I-69 in Hernando, MS||I-69 in Millington, TN||2015||current||Construction completed in October 2018; co-signed with SR 304 in MS and SR 385 in TN|
|I-169||18.7||30.1||US 45W/US 51 in Union City, TN||US 45E/SR 43 in Martin, TN||proposed||—||Proposed for designation along SR 22 once upgraded to Interstate standards|
|I-469||30.83||49.62||I-69 in Fort Wayne, IN||I-69 in Fort Wayne, IN||1995||current|
|I-169||1.50||2.41||Port of Brownsville main entrance in Brownsville, TX||I-69E/US 77/US 83 in Olmito, TX||2015||current||Currently under construction; partially open and co-signed with SH 550|
|I-369||3.50||5.63||I-30/US 59 in Texarkana, TX||US 59/SH 93 in Texarkana, TX||2013||current||Partially completed in 2013|
|I-270||5.31||8.55||I-25/US 36 at Welby, CO||I-70/US 36 at Denver, CO||1965||current|
|I-470||—||—||Beltway around Denver Metro, CO||—||—||Now part of SH 470|
|I-270||50.59||81.42||I-55/I-255 in Mehlville, MO||I-55/I-70 near Troy, IL||1956||current|
|I-470||13.72||22.08||I-70 in Topeka, KS||I-70/Kansas Turnpike in Topeka, KS||1960||current|
|I-670||2.81||4.52||I-70 in Kansas City, KS||I-70 in Kansas City, MO||1968||current|
|I-170||2.30||3.70||I-70 in Baltimore, MD||US 40 in Baltimore, MD||1969||1983||Canceled|
|I-270||32.60||52.46||I-70 near Frederick, MD||I-495 north of Bethesda, MD||1975||current|
|2.10||3.38||I-270 east of Potomac, MD||I-495 northwest of Bethesda, MD||1975||current||Serves as an alternate connector for Virginia travelers|
|I-370||2.54||4.09||I-270 in Gaithersburg, MD||MD 200 in Derwood, MD||1988||current|
|I-170||11.17||17.98||I-64/US 40 in Richmond Heights, MO||I-270 in Hazelwood, MO||1956||current|
|I-470||16.72||26.91||I-49/I-435 in Kansas City, MO||I-70 in Independence, MO||1983||current|
|I-270||54.97||88.47||Beltway around Columbus, OH||1964||current|
|I-470||6.69||10.77||I-70 near Blaine, OH||I-70 in Elm Grove, WV||1976||current|
|I-670||9.37||15.08||I-70 in Columbus, OH||I-270 near John Glenn Columbus International Airport||2003||current|
|I-271||46.06||74.13||I-71 near Medina, OH||I-90 in Willoughby Hills, OH||1964||current|
|I-471||5.75||9.25||I-275 near Newport, KY||I-71 in Cincinnati, OH||1981||current|
|I-172||19.69||31.69||I-72 in Quincy, IL||US 24 in Quincy, IL||1995||current|
|I-474||14.88||23.95||I-74 in Peoria, IL||I-74 in Morton, IL||1973||current|
|I-274||16.83||27.09||US 158 near Clemmons, NC||Future I-74/Future I-285/US 52 in Bethania, NC||proposed||—||Proposed route in Winston-Salem, NC|
|I-175||1.44||2.32||I-275 in St. Petersburg, FL||SR 687 in St. Petersburg, FL||1980||current|
|I-275||60.64||97.59||I-75 near Memphis, FL||I-75 in Wesley Chapel, FL||1973||current|
|I-375||1.34||2.16||I-275 in St. Petersburg, FL||US 92 in St. Petersburg, FL||1979||current|
|I-175||—||—||US 82 in Albany, GA||I-75 in Cordele, GA||—||—||Now part of SR 300|
|I-475||15.83||25.48||I-75 in Macon, GA||I-75 in Macon, GA||1965||current|
|I-575||30.97||49.84||I-75 in Kennesaw, GA||SR 5 west of Nelson, GA||1985||current|
|I-675||11.04||17.77||I-75 in Stockbridge, GA||I-285 southeast of Atlanta, GA||1987||current|
|I-275||83.71||134.72||Beltway around Cincinnati, OH||1962||current||Runs through Indiana, Ohio and Kentucky; I-75 does not run through Indiana|
|I-275||35.01[a]||56.34||I-75 near Monroe, MI||I-96, I-696 and M-5 in Farmington Hills, MI||1977||current|
|I-375||1.06||1.71||BS I-375 in Detroit, MI||I-75 in Detroit, MI||1964||current|
|I-475||16.99||27.34||I-75 near Grand Blanc, MI||I-75/US 23 near Mount Morris, MI||1973||current||Runs east and north of Flint, MI|
|I-675||7.72||12.42||I-75/US 23 near Saginaw, MI||I-75/US 23 near Zilwaukee, MI||1971||current|
|I-475||20.37||32.78||I-75 in Perrysburg, OH||I-75 in Toledo, OH||1964||current|
|I-675||26.53||42.70||I-75 near Miamisburg, OH||I-70 near Medway, OH||1987||current|
|I-175||—||—||I-75 in Chattanooga, TN||I-75 in Lexington, KY||—||—|
|I-275||2.98||4.80||I-40 in Knoxville, TN||I-75/I-640 in Knoxville, TN||1982||current|
|I-475||—||—||I-40/I-75 near Knoxville, TN||I-75 near Knoxville, TN||—||—||Canceled|
|I-676||6.90||11.10||I-76/US 30 in Philadelphia, PA||I-76 in Camden, NJ||1991||current|
|I-176||11.33||18.23||I-76/Pennsylvania Turnpike in Morgantown, PA||US 422 near Reading, PA||1964||current|
|I-276||29.78||47.93||I-76 in King of Prussia, PA||I-95/I-295 in Bristol Township, PA||1964||current||Truncated in 2018, replaced by I-95|
|I-376||78.70||126.66||I-80 near Hermitage, PA||I-76/US 22 in Monroeville, PA||1972||current|
|I-476||129.61||208.59||I-95 near Chester, PA||I-81/US 6/US 11 near Clarks Summit, PA||1992||current|
|I-876||1.57||2.53||PA 885 in Pittsburgh, PA||I-279/PA 28 in Pittsburgh, PA||1970||1971||Short lived renumbering of I-479, now I-579|
|I-277||4.46||7.18||Beltway around uptown Charlotte, NC||1981||current|
|I-277||4.14||6.66||I-76 in Akron, OH||I-77 in Akron, OH||1970||current|
|I-378||—||—||—||—||1968||1971||Replaced by PA Route 378|
|I-278||35.62||57.32||US 1/9 in Linden, NJ||Bruckner Interchange in Bronx, NY||1961||current||Does not intersect with parent route I-78|
|I-478||2.14||3.44||I-278 in Brooklyn, NY||NY 9A in Manhattan, NY||1971||current||Unsigned; does not intersect with parent route I-78|
|I-678||14.33||23.06||John F. Kennedy International Airport in Queens, NY||Bruckner Interchange in Bronx, NY||1965||current||Does not intersect with parent route I-78|
|I-878||0.70||1.13||I-678 in Queens, NY, near John F. Kennedy International Airport||JFK Expressway in Queens, NY, near JFK Airport||1970||current||Unsigned; does not intersect with parent route I-78; eastbound only|
|I-179||—||—||McKean Township, PA||Erie, PA||1958||1968||Replaced by its parent route, I-79|
|I-279||13.32||21.44||I-376/US 22/US 30 in Pittsburgh, PA||I-79 in Franklin Park, PA||1972||current|
|I-479||1.57||2.53||PA 885 in Pittsburgh, PA||I-279/PA 28 in Pittsburgh, PA||1966||1970||Early number for I-579|
|I-579||1.57||2.53||PA 885 in Pittsburgh, PA||I-279/PA 28 in Pittsburgh, PA||1971||current|
|I-180||—||—||US 101 in San Rafael, CA||I-80 near Berkeley, CA||1978||1991||Temporary designation of what was formerly part of SR 17, now part of I-580|
|I-280||57.22||92.09||I-680/US 101 in San Jose, CA||King Street in San Francisco, CA||1964||current|
|I-380||1.671||2.689||I-280 in San Bruno, CA||US 101 in San Bruno, CA||1964||current|
|I-480||—||—||I-80 in San Francisco, CA||Sansome Street in San Francisco, CA||1957||1968||Was to be the Embarcadero Freeway; downgraded to a state highway in 1968 and fully decommissioned in 1991|
|I-580||75.63||121.71||US 101 in San Rafael, CA||I-5 near Westley, CA||1964||current||Segments were originally part of I-5W|
|I-680||70.52||113.49||I-280/US 101 in San Jose, CA||I-80 in Cordelia, CA||1955||current||Originally SR 21|
|I-780||6.50||10.46||I-80 in Vallejo, CA||I-680 in Benicia, CA||1955||current||Originally part of I-680|
|I-880||47.22||75.99||I-280/SR 17 in San Jose, CA||I-80/I-580 in Oakland, CA||1983||current||Originally part of SR 17|
|I-880||—||—||I-80 in West Sacramento, CA||I-80 in Sacramento, CA||1971||1983||Now part of I-80|
|I-980||2.03||3.27||I-880 in Oakland, CA||I-580/SR 24 in Oakland, CA||1981||current|
|I-580||30.09||48.43||US 50 in Carson City, NV||I-80 in Reno, NV||2012||current||Runs concurrently with US 395|
|I-180||13.19||21.23||IL 26/IL 71 in Hennepin, IL||I-80 near Princeton, IL||1969||current|
|I-280||26.98||43.42||I-80 near Davenport, IA||I-74/I-80 near Colona, IL||1990||current|
|I-380||73.05||117.56||I-80 near Iowa City, IA||US 218 in Waterloo, IA||1985||current||Connects Cedar Rapids, IA, with I-80|
|I-480||4.90||7.89||I-80/US 75 in Omaha, NE||I-29/US 6 in Council Bluffs, IA||1966||current|
|I-680||16.49||26.54||I-80 in Omaha, NE||I-29 near Crescent, IA||1966||current|
|I-880||16.57||26.67||I-29 near Loveland, IA||I-80 near Neola, IA||2019||current||Former section of I-680|
|I-180||3.18||5.12||US 34 in Lincoln, NE||I-80/US 34/US 77 in Lincoln, NE||1965||current|
|I-280||—||—||—||—||1958||1965||Redesignated as I-680|
|I-580||1.60||2.57||I-480 in Omaha, NE||Lake Street in Omaha, NE||1976||1982||Now part of US 75|
|I-280||17.85||28.73||I-80 in Parsippany-Troy Hills, NJ||I-95/New Jersey Turnpike in Kearny, NJ||1958||current|
|I-280||12.41||19.97||I-75 in Toledo, OH||I-80/I-90/Ohio Turnpike in Lake Township, OH||1959||current|
|I-380||—||—||I-76/I-77 in Akron, OH||I-271 in Macedonia, OH||proposed||—||Proposed designation for SR 8 between Akron and Macedonia|
|I-480||41.77||67.22||I-80/Ohio Turnpike in North Ridgeville, OH||I-80/Ohio Turnpike in Streetsboro, OH||1971||current|
|I-680||16.43||26.44||I-76/Ohio Turnpike in North Lima, OH||I-80/SR 11 near Mineral Ridge, OH||1964||current|
|I-180||28.85||46.43||US 15/US 220 in Williamsport, PA||I-80/PA 147 near Milton, PA||1984||current|
|I-180||—||—||—||—||—||1964||Original number for I-176 when I-76 was I-80S|
|I-280||—||—||—||—||1958||1964||Now part of Pennsylvania Turnpike|
|I-380||24.76||39.85||I-80 in Tunkhannock Township, PA||I-81/I-84/US 6 in Dunmore, PA||1973||current|
|I-480||—||—||—||—||1958||1964||Early number for I-476 when I-76 was I-80S|
|I-680||—||—||—||—||1958||1964||Original number for I-676 when I-76 was I-80S|
|I-180||1.09||1.75||I-80 in Cheyenne, WY||I-80 Bus./US 30 in Cheyenne, WY||1984||current||Not built to Interstate Highway standards|
|I-481||15.04||24.20||I-81 in Onondaga, NY||I-81/NY 481 in North Syracuse, NY||1970||current||Will be decommissioned when I-81 is rerouted onto the freeway|
|I-781||4.30||6.92||I-81 in Pamelia, NY||Fort Drum main gate in Le Ray, NY||2012||current|
|I-381||1.67||2.69||SR 381 in Bristol, VA||I-81 in Bristol, VA||1961||current|
|I-581||6.64||10.69||US 220/SR 24 in Roanoke, VA||I-81 near Hollins, VA||1955||current|
|I-181||23.85||38.38||US 321/SR 67 in Johnson City, TN||US 11W/SR 1 in Kingsport, TN||1985||2007||Now part of I-26|
|I-182||15.19||24.45||I-82/US 12 near Richland, WA||US 12/US 395 in Pasco, WA||1969||current|
|I-283||2.91||4.68||I-76/Pennsylvania Turnpike near Highspire, PA||I-83/US 322/Capital Beltway near Harrisburg, PA||1972||current|
|I-384||8.20||13.20||I-84/US 6 in East Hartford, CT||US 6/US 44 in Bolton, CT||1984||current|
|I-684||28.47||45.82||I-287 near White Plains, NY||NY 22 near Brewster, NY||1974||current||Also crosses into Connecticut|
|I-184||3.62||5.83||I-84 in Boise, ID||US 20/US 26 in Boise, ID||1990||current|
|I-685||14.00||22.53||I-65 in downtown Montgomery, AL||I-85 in Montgomery, AL||proposed||—||Future designation for I-85 in Montogomery once the Montgomery Outer Loop is completed and I-85 is routed onto it|
|I-185||49.30||79.34||US 27/US 280/SR 520 in Columbus, GA||I-85 near LaGrange, GA||1979||current|
|I-285||63.98||102.97||Beltway around Atlanta, GA||1969||current|
|I-485||5.9||9.5||I-75/I-85 in Atlanta, GA||I-85 in Atlanta, GA||1964||1975||Now Freedom Parkway, was planned to relieve traffic along Downtown Connector (I-75/85) through downtown Atlanta|
|I-985||24.04||38.69||I-85 near Buford, GA||SR 369 near Gainesville, GA||1985||current|
|I-285||22.8||36.7||I-85/I-85 Bus./US 29/US 52/US 70 near Lexington, NC||I-40/US 52/US 311/NC 8 in Winston-Salem, NC||2018||current||An unconfirmed section of Future I-285 is to continue north of I-40 for 10 miles (16 km) along US 52, through downtown Winston-Salem, to the proposed Winston-Salem Northern Beltway.|
|I-485||66.68||107.31||Beltway around Charlotte, NC||1988||current|
|I-685||—||—||Greensboro, NC||Dunn, NC||proposed||—||Future designation that will run concurrently with US 421 once the latter route is upgraded to interstate standards|
|I-785||2.21||3.56||I-40/I-85/I-840/I-85 Bus. in Greensboro, NC||US 70 in Greensboro, NC||2013||current||Future northern terminus at US 29/US 58/US 360/US 58 Bus. in Danville, VA|
|I-885||8.566||13.786||I-40/NC 885 in Research Triangle Park, NC||I-85/US 70/US 15 in Durham, NC||2022||current|
|I-185||17.70||28.49||I-385 near Mauldin, SC||US 29 in Greenville, SC||1955||current|
|I-385||42.16||67.85||I-26 near Clinton, SC||US 276 in Greenville, SC||1962||current|
|I-585||2.25||3.62||US 176/US 221/SC 9 in Spartanburg, SC||I-85 Bus./US 176 near Spartanburg, SC||1962||current|
|I-287||98.72||158.87||I-95/New Jersey Turnpike/Route 440 in Edison, NJ||I-95 in Rye, NY||1961||current|
|I-587||1.21||1.95||I-87/New York State Thruway/NY 28 in Kingston, NY||NY 28/NY 32 in Kingston, NY||1960||current|
|I-587||55.9||90.0||I-87/US 64 near Zebulon, NC||US 264 near Greenville, NC||2022||current||Former section of US 264|
|I-787||10.16||16.35||I-87/New York State Thruway in Albany, NY||NY 7 in Green Island, NY||1968||current|
|I-189||1.49||2.40||US 7 in South Burlington, VT||I-89 in South Burlington, VT||1980||current|
|I-190||3.07||4.94||O'Hare International Airport in Chicago, IL||I-90 in Chicago, IL||1978||current|
|I-290||29.84||48.02||I-90/IL 53 in Rolling Meadows, IL||I-90/I-94/Ida B. Wells Drive in Chicago, IL||1972||current|
|I-490||—||—||I-294 in Franklin Park, IL||I-90 in Des Plaines, IL||proposed||—||Proposed route number for the O'Hare West Bypass|
|I-190||19.26||31.00||I-290 in Worcester, MA||Route 2 in Leominster, MA||1983||current|
|I-290||20.16||32.44||I-395 in Auburn, MA||I-495 in Marlborough, MA||1970||current|
|I-190||28.34||45.61||I-90/New York State Thruway in Cheektowaga, NY||Highway 405 at Lewiston, NY||1959||current|
|I-290||9.80||15.77||I-190 in Tonawanda, NY||I-90/New York State Thruway in Williamsville, NY||1964||current|
|I-390||76.06||122.41||I-86/NY 17 in Avoca, NY||I-490 in Gates, NY||1973||current|
|I-490||37.40||60.19||I-90/New York State Thruway in Bergen, NY||I-90/New York State Thruway in Victor, NY||1970||current|
|I-590||5.31||8.55||I-390 in Brighton, NY||I-490/NY 590 in Rochester, NY||1980||current|
|I-690||14.19||22.84||I-90/New York State Thruway/NY 690 in Van Buren, NY||I-481 in East Syracuse, NY||1962||current|
|I-790||2.41||3.88||I-90/New York State Thruway in Deerfield, NY||NY 5A/NY 55 in Utica, NY||1961||current|
|I-890||9.35||15.05||I-90/New York State Thruway in Rotterdam, NY||I-90/New York State Thruway in Guilderland, NY||1962||current|
|I-990||6.35||10.22||I-290 in Amherst, NY||NY 263 near Lockport, NY||1985||current||Highest numbered Interstate in the Interstate system|
|I-490||2.43||3.91||I-71/I-90 in Cleveland, OH||East 55th Street in Cleveland, OH||1990||current|
|I-190||1.72||2.77||I-90 in Rapid City, SD||US 16 in Rapid City, SD||1962||current|
|I-291||6.02||9.69||I-91 in Windsor, CT||I-84 in Manchester, CT||1994||current|
|I-691||8.38||13.49||I-84 at the Southington-Cheshire, CT town line||I-91 in Meriden, CT||1988||current|
|I-291||5.44||8.75||I-91 in Springfield, MA||I-90/Massachusetts Turnpike in Chicopee, MA||1972||current|
|I-391||4.46||7.18||I-91 in Chicopee, MA||High Street in Holyoke, MA||1970||current|
|I-293||11.18||17.99||I-93/NH 101 in Manchester, NH||I-93/Everett Turnpike in Hooksett, NH||1976||current|
|I-393||4.60||7.40||I-93 in Concord, NH||NH 9 in Pembroke, NH||1979||current|
|I-294||53.42||85.97||I-80/I-94 in South Holland, IL||I-94 in Deerfield, IL||1968||current|
|I-194||3.38||5.44||I-94 in Battle Creek, MI||M-66 in Battle Creek, MI||1961||current|
|I-394||9.75||15.69||I-494/US 12 in Minnetonka, MN||4th Street in Minneapolis, MN||1991||current|
|I-494||42.94||69.11||I-94/I-694 in Maple Grove, MN||I-94/I-694 in Woodbury, MN||1985||current||Western and southern half of the Minneapolis–St. Paul beltway|
|I-694||30.77||49.52||I-94/I-494 in Maple Grove, MN||I-94/I-494 in Woodbury, MN||1970||current||Northern and eastern half of the Minneapolis–St. Paul beltway|
|I-194||1.20||1.93||McKenzie Drive near Bismarck, ND||I-94 near Mandan, ND||1958||current||Unsigned|
|I-794||3.75||6.04||I-43/I-94 in Milwaukee, WI||WIS 794 in Milwaukee, WI||1980||current|
|I-894||4.70||7.56||I-41/I-94 in Milwaukee, WI||I-41/I-43/I-94 in Milwaukee, WI||1966||current||Completely concurrent with I-41|
|I-395||66.60||107.18||I-95 in East Lyme, CT||I-290 in Auburn, MA||1983||current|
|I-295||92.30||148.54||I-95/I-495 in New Castle, DE||I-95 in Bristol Township, PA||1994||current||Extended into Pennsylvania in 2018|
|I-495||11.47||18.46||I-95/I-295 in Newport, DE||I-95 in Lower Chichester Township, PA||1977||current|
|I-895||—||—||—||—||1979||1980||Now part of I-95|
|I-195||2.41||3.88||I-395 in Washington D.C.||US 50 in Washington D.C.||proposed||—||Currently I-395; I-395 will be rerouted onto I-695|
|I-395||13.39||21.55||I-95/I-495 in Springfield, VA||US 50 in Washington, DC||1977||current||Original route of I-95 that was proposed to continue through Washington, DC|
|I-495||64||103||Beltway around Washington, DC||1961||current||Capital Beltway; runs through Virginia, Maryland and a small sliver of Washington, DC, over the Wilson Bridge|
|I-695||2.00||3.22||I-395 in Washington, DC||I-295 in Washington, DC||1958||current||Unsigned until 2011; future plans call for the route number to be replaced by an extension of I-395|
|I-195||4.42||7.11||I-95/SR 112 in Miami, FL||SR 905 in Miami Beach, FL||1961||current|
|I-295||61.04||98.23||Beltway around Jacksonville, FL||1970||current|
|I-395||1.29||2.08||I-95 in Miami, FL||MacArthur Causeway at Watson Island, Miami, FL||1971||current|
|I-595||12.86||20.70||I-75/SR 869 in Weston, FL||US 1 in Fort Lauderdale, FL||1990||current|
|I-795||7.4||11.9||I-95 south of Jacksonville, FL||I-295 in Jacksonville, FL||proposed||—||Currently signed as SR 9B pending approval of the interstate designation from the AASHTO|
|I-195||1.55||2.49||I-95/Maine Turnpike in Saco, ME||SR 5 in Saco, ME||1980||current|
|I-295||53.11||85.47||I-95/Maine Turnpike in Scarborough, ME||I-95/Maine Turnpike in Gardiner, ME||1960||current|
|I-395||4.99||8.03||I-95/US 2/SR 100 in Bangor, ME||US 1A in Brewer, ME||2008||current|
|I-495||3.70||5.95||I-95/Maine Turnpike in Portland, ME||I-295/US 1 in Falmouth, ME||2004||current||Unsigned|
|I-195||4.71||7.58||I-95/MD 166 near Catonsville, MD||Baltimore-Washington International Airport||1990||current|
|I-395||1.98||3.19||I-95 in South Baltimore, MD||West Pratt Street in Baltimore, MD||1981||current|
|I-595||19.97||32.14||I-95/I-495/US 50 near Washington, DC||US 50/US 301/MD 70 in Annapolis, MD||2011||current||Unsigned designation for US 50|
|I-695||30.57||49.20||Beltway around Baltimore, MD||1958||current|
|I-795||8.99||14.47||I-695 in Pikesville, MD||MD 140 in Reisterstown, MD||1985||current|
|I-895||11.44||18.41||I-95 near Elkridge, MD||I-95 in Baltimore, MD||1979||current|
|I-295||8.05||12.96||I-95/I-495 near Forest Heights, MD||I-695 in Washington, DC||1964||current|
|I-195||44.55||71.70||I-95 in Providence, RI||I-495/Route 25 in Wareham, MA||1958||current|
|I-295||26.58||42.78||I-95 in Warwick, RI||I-95 in Attleboro, MA||1969||current|
|I-495||121.56||195.63||I-195/Route 25 in Wareham, MA||I-95 in Salisbury, MA||1957||current|
|I-695||—||—||I-95 in Roxbury, MA||I-93 in Charlestown, MA||1955||1971||Canceled; was to have been built in connection with a planned alignment of I-95 through downtown Boston|
|I-895||—||—||Route 37/I-295 in Cranston, RI||I-95/I-295 in Attleboro, MA||1968||1982||Canceled; would have supplemented I-295 to create a full Beltway around Providence, RI|
|I-195||34.17||54.99||I-295 in Hamilton Township, NJ||Route 34 in Wall Township, NJ||1968||current|
|I-895||—||—||I-295 in Burlington, NJ||I-95 in Bristol, PA||1963||1981||Never built|
|I-295||9.79||15.76||NY 25/NY 24 in Queens, NY||Bruckner Interchange in Bronx, NY||1970||current|
|I-495||71.02||114.30||Queens Midtown Tunnel in Manhattan, NY||CR 58 in Riverhead, NY||1958||current|
|I-695||1.77||2.85||I-95 in Bronx, NY||I-295 in Bronx, NY||1986||current|
|I-895||1.12||1.80||I-278 in Bronx, NY||I-95 in Bronx, NY||1970||2017||Downgraded to a boulevard and designated as NY 895|
|I-295||34.0||54.7||Cliffdale Road in Fayetteville, NC||I-95 and US 13 near Eastover, NC||2019||current||Unfinished Fayetteville Outer Loop; expected to be completed in its entirety in Summer 2026|
|I-495||4.10||6.60||I-440/US 64/US 64 Bus. in Raleigh, NC||I-540/US 64/US 264 in Knightdale, NC||2013||2017||Now part of I-87|
|I-795||25.46||40.97||US 70/US 117 in Goldsboro, NC||I-95/US 264 in Wilson, NC||2007||current|
|I-695||—||—||I-95 near Philadelphia International Airport||I-95 in Philadelphia, PA||1964||1977||Never built|
|I-195||3.24||5.21||SR 195 in Richmond, VA||I-64/I-95 in Richmond, VA||1970||current|
|I-295||52.56||84.59||I-95 near Petersburg, VA||I-64 near Short Pump, VA||1980||current|
|I-595||—||—||I-395 near Arlington, VA||US 1 at Ronald Reagan Washington National Airport||—||—||Now part of US 1|
|I-895||—||—||I-95 near Richmond, VA||I-295 near Richmond, VA||1996||2002||Currently designated as SR 895, it was originally planned as an Interstate designation, but did not get approved by AASHTO|
|I-495||—||—||—||—||1956||1958||Early number of I-476|
|I-196||37.07||59.66||US 31 in Norton Shores, MI||I-96/US 16 in Grand Rapids, MI||1959||1963||Now the western end of I-96|
|I-196||80.65||129.79||I-94/US 31 near Benton Harbor, MI||I-96/M-37 in Grand Rapids, MI||1963||current|
|I-296||3.43||5.52||I-196 in Grand Rapids, MI||I-96/M-37 in Walker, MI||1962||current||Unsigned since 1979|
|I-496||11.78||18.96||I-69/I-96 near Lansing, MI||I-96 and US 127 near Lansing, MI||1970||current|
|I-696||29.39||47.30||I-96/I-275 & M-5 in Novi, MI||I-94 in Roseville, MI||1989||current|
|I-197||3.44||5.54||—||—||—||1980c.||Replaced by I-595|
|I-297||—||—||—||—||—||1987||Withdrawn from request, replaced by MD 3|
- ^ Weingroff, Richard F. (Summer 1996). "Federal-Aid Highway Act of 1956, Creating the Interstate System". Public Roads. Washington, DC: Federal Highway Administration. 60 (1). Retrieved March 16, 2012.
- ^ a b c DeSimone, Tony (October 31, 2002). "Interstate Route Numbering". Route Log and Finder List. Federal Highway Administration. Retrieved February 3, 2008.
- ^ a b Adderly, Kevin (December 31, 2015). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways as of December 31, 2015". Route Log and Finder List. Federal Highway Administration. Retrieved February 6, 2016.
- ^ Special Committee on U.S. Route Numbering (December 8, 1990). "Report of the Special Committee on U.S. Route Numbering to the Executive Committee" (PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. Archived from the original (PDF) on October 16, 2017.
- ^ Warring, KS (January 2, 2008). "Interstate 905 Freeway Interchanges" (PDF). California Numbered Exit Uniform System. Sacramento: California Department of Transportation. Retrieved February 5, 2009.
- ^ Cavanaugh, Patricia (October 2006). "Politics and Freeways: Building the Twin Cities Interstate System". University of Minnesota.
- ^ Tennessee Department of Transportation (October 31, 2003). "TDOT Announces Decision on State Route 840 North" (PDF) (Press release). Tennessee Department of Transportation. Archived from the original (PDF) on November 27, 2007.
- ^ Federal Highway Administration (October 31, 2002). "Table 2: Auxiliary Routes of the Dwight D. Eisenhower National System of Interstate and Defense Highways as of October 31, 2002". Route Log and Finder List. Federal Highway Administration. Retrieved July 8, 2007.
- ^ Dozier, Daniel A. (September 5, 2013). "Request for I-69 Designation for I-164 from I-64 to US 41" (PDF). Letter to Richard J. Marquis. Indianapolis: Indiana Department of Transportation. Archived from the original (PDF) on March 4, 2016. Retrieved January 9, 2015 – via American Association of State Highway and Transportation Officials.
- ^ Highway Information Services Division (December 31, 2013). Highway Location Reference. Maryland State Highway Administration. Retrieved March 2, 2012.
- Montgomery County (PDF).
- ^ a b c Michigan Department of Transportation (2021). Next Generation PR Finder (Map). Michigan Department of Transportation. Retrieved October 11, 2021.
- ^ Rand McNally (2008). "Michigan: Cities" (Map). The Road Atlas. 1 in≈5 mi. Chicago: Rand McNally. p. 52. Detroit & Vicinity inset. § I3. ISBN 0-528-93981-5. OCLC 226315010.
- ^ Google (February 24, 2010). "Overview Map of I-275" (Map). Google Maps. Google. Retrieved February 24, 2010.
- ^ "Ask SAM: Upgrades needed before US 52 can be called I-285". Winston-Salem Journal. January 10, 2014. Retrieved January 10, 2014.
- ^ "NCDOT: Project U-2826". Archived from the original on October 29, 2011. Retrieved April 17, 2014.
- ^ "State Seeking Future Interstate Designation for US 264 to Greenville". North Carolina Governor's Office (Press release). Archived from the original on November 10, 2016. Retrieved November 10, 2016.
- ^ Borggren, Erica J. (October 6, 2014). "I 490 Illinois Establish" (PDF). Archived from the original (PDF) on March 3, 2016.
- ^ DeBonis, Mike (November 28, 2011). "Interstate 695 Reappears in D.C." The Washington Post.
- ^ Highway Information Services Division (December 31, 2013). Highway Location Reference. Maryland State Highway Administration. Retrieved September 24, 2012.
- Anne Arundel County (PDF). pp. 6–7.
- Baltimore County (PDF). pp. 18–20, 162.
- ^ Special Committee on U.S. Route Numbering (September 24, 2017). "Special Committee on U.S. Route Numbering" (PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. p. 4. Archived from the original (PDF) on June 3, 2019. Retrieved October 21, 2017.
- Geographic data related to List of auxiliary Interstate Highways at OpenStreetMap
- 3-digit Interstates at Kurumi.com