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In the U.S. state of South Dakota, Interstate 90 (I-90) traverses east–west through the southern half of the state.

Interstate 90 marker

Interstate 90
Purple Heart Memorial Highway
I-90 highlighted in red
Route information
Defined by SDCL §31-4-184
Maintained by SDDOT
Length412.76 mi[1] (664.27 km)
Major junctions
West end I-90 / US 14 at Wyoming state line
  I-190 / US 16 in Rapid City
I-29 in Sioux Falls
I-229 in Sioux Falls
East end I-90 at Minnesota state line
CountiesLawrence, Meade, Pennington, Jackson, Jones, Lyman, Brule, Aurora, Davison, Hanson, McCook, Minnehaha
Highway system
  • South Dakota Highways
SD 89SD 101


Route descriptionEdit

Interstate 90 enters South Dakota in Lawrence County as a four-lane divided highway. It enters concurrently with U.S. Route 14, and passes through the town of Spearfish, where it shares another concurrency with U.S. Route 85 from exit 10 to exit 17. From there it passes several miles north and east of the tourist town of Deadwood before entering Meade County, going just to the west of Sturgis. Another concurrency is with South Dakota Highway 34 from exit 23 at Whitewood to exit 30, the west exit of Sturgis, where there starts a concurrency with SD 79. The freeway generally passes along the north and east edges of the Black Hills.

The route then enters Pennington County, where it passes through the northern edge of Rapid City, gateway to the Black Hills and the nearest passing to Mount Rushmore National Memorial, as well as other scenic attractions including Custer State Park and the Needles Highway. Rapid City is also where the interstate has its westernmost auxiliary route, Interstate 190, which links the interstate to the western edge of the downtown area. SD 79's concurrency ends at exit 61 on the east side of the city. From Rapid City, the route heads east, passing between Box Elder to the south and Ellsworth Air Force Base to the north before heading towards Wall on to Jackson County. Exits 110 and 131 for Badlands National Park to the south (SD 240) are within 15 miles (24 km) either way of the county line. The concurrency for US-14 ends at exit 112 just east of Wall; here US-14 runs due east and will connect to the city of Philip and the capital city of Pierre.

The Lake Francis Case portion of the Missouri River viewed from a rest stop just south of Chamberlain; the pre-interstate Chamberlain Bridge is in the center.

From there, the route passes mostly east–west through Jackson and Jones counties. There are short concurrencies with SD 73 (from the west entering Kadoka) and SD 63 in Jackson County. Interstate 90 crosses the Central Time/Mountain Time Zone boundary on the west edge of Jones County. Then at Murdo, a concurrency begins with U.S. Route 83 at exit 192 and continues to exit 212. It is in Lyman County, at exit 212 in Vivian, that the highway provides its closest link to the capital of Pierre, along US-83, some 35 miles (56 km) north. The road crosses the Missouri River at Lake Francis Case, between the towns of Oacoma and Chamberlain, also crossing into Brule County. I-90 Business Loop runs from exit 260 at Oacoma to downtown Chamberlain across the Missouri River on the nearby Chamberlain Bridge, and returns to I-90 at exit 265. Beginning there is a short concurrency with SD 50 heading to Pukwana, and also in Brule County is another short concurrency with SD 45 starting at Kimball.

I-90 then continues through Aurora County (connecting to White Lake and Plankinton), Davison County (where Mt. Vernon, Mitchell and the Corn Palace are located), Hanson County (Alexandria), and McCook County (Salem). Then comes the state's most populous county, Minnehaha. After passing the communities of Humboldt and Hartford, the interstate intersects the only other major interstate in the state, Interstate 29, at Sioux Falls, the largest city. Just east of Interstate 29 is where Interstate 90 meets the northern terminus of Interstate 229. East of Brandon and northeast of Valley Springs, it then ends its trip through South Dakota of 412 miles (663 km) before entering Minnesota and Rock County, just west of the towns of Beaver Creek and Manley.

Since April 2015 the speed limit is 80 miles per hour (130 km/h), except it is 65 miles per hour (105 km/h) between I-229 and Marion Road in Sioux Falls; or through Rapid City. The speed limit remains 75 miles per hour (121 km/h) between Rapid City and the Wyoming state line.

Codified lawEdit

The South Dakota section of I-90 is defined at South Dakota Codified Laws § 31-4-184.[2]


On May 24, 2012, the South Dakota Transportation Commission declared the entire length of I-90 as part of the National Purple Heart Trail, naming it the Purple Heart Memorial Highway.[3]

Removal of exit 66Edit

In the city of Box Elder, exit 66, which crossed South Dakota Highway 435, was closed on October 1, 2003, after a 10-month delay.[4] The exit was closed and removed as a result of the department of transportation's efforts to move traffic away from a potential crash site at the end of the Ellsworth AFB runway. The partial cloverleaf interchange of exit 66 was also demolished shortly thereafter. Exit 67, which was constructed not too long before the closure of exit 66, is now used as the main entrance and exit feeder to the base, and it is less likely to be impacted by a potential crash.[5] Local citizens and officials feared the lack of entrances which access the Ellsworth Air Force Base would cause traffic issues, and moving businesses from near the old exit would cause some to close and affect tax revenue. Land near exit 66 began to be purchased in 2004, including the former McDonald's property.[6]

Exit listEdit

Lawrence0.000.00   I-90 / US 14 west – GilletteContinuation into Wyoming
2.253.622McNenny State Fish Hatchery
Spearfish8.9614.428McGuigan Road – Spearfish, Black Hills National Forest
10.2616.5110   I-90 Bus. east (North Avenue) / US 85 north – Spearfish, Belle FourcheWestern end of US 85 concurrency
12.3219.8312Jackson Boulevard – Spearfish, Black Hills State University
14.4223.2114   I-90 Bus. west / US 14A (27th Street) / Black Hills National Forest Scenic Byway – Spearfish Canyon
18.1629.2317  US 85 south – Deadwood, LeadEastern end of US 85 concurrency
Whitewood23.7338.1923  SD 34 west – Whitewood, Belle FourcheWestern end of SD 34 concurrency
MeadeSturgis30.2848.7330     I-90 Bus. / SD 34 east / SD 79 north (Lazelle Street) / US 14A west – Sturgis, Deadwood, LeadEastern end of SD 34 concurrency; western end of SD 79 concurrency
32.4152.1632   I-90 Bus. west (Junction Avenue) – SturgisServes Sturgis Regional Hospital
34.8156.0234Black Hills National Cemetery
37.0159.5637Pleasant Valley Road
Tilford40.2064.7040Tilford Road, Bethlehem Road – Tilford
Piedmont44.6671.8744Bethlehem Road – Piedmont
46.1474.2646Elk Creek Road – Piedmont, Summerset
Summerset48.4377.9448Stagebarn Canyon Road – Summerset
Black Hawk52.3884.3052  I-90 Bus. east (Peaceful Pines Road) – Black Hawk, Rapid City
PenningtonRapid City55.6689.5855Deadwood Avenue – Rapid City
57.7692.9657   I-190 south / US 16 west – Rapid City, Mount Rushmore, Black Hills National ForestTrumpet interchange; I-190 exits 1A–B
58.3193.8458Haines Avenue – Rapid CitySingle-point urban interchange (SPUI)
59.1995.2659La Crosse Street – Rapid City
60.4897.3360  I-90 Bus. west (North Street) – Rapid CitySPUI
   US 16 Truck / SD 79 south – Rapid City, Mount Rushmore, Crazy Horse
Eastern end of SD 79 concurrency; SPUI
Box Elder63.42102.0663Box Elder, Ellsworth AFB Commercial GateEastbound exit and westbound entrance
66.17106.4966  SD 435 – Ellsworth AFBClosed October 1, 2003[5]
67.15108.0767Liberty Boulevard – Box Elder, Ellsworth AFB Main GateSigned as exits 67A (south) and 67B (north) eastbound, Partial cloverleaf interchange
New Underwood78.29126.0078161st Avenue – New Underwood
84.24135.5784167th Avenue
88.23141.9988171st AvenueEastbound exit and westbound entrance
90.25145.2490173rd Avenue
Wasta98.14157.9498Base Line Road – WastaPartial cloverleaf interchange
101.23162.91101Jensen RoadPartial cloverleaf interchange
107.85173.57107Cedar Butte Road
Wall109.82176.74109  I-90 Bus. east / W. 4th Avenue – Wall
110.98178.60110   I-90 Bus. west (Glenn Street) / SD 240 east (Badlands Loop) – Wall, Badlands
112.01180.26112  US 14 east – Philip, PierreEastern end of US 14 concurrency, trumpet interchange
116.94188.20116239th Street
121.98196.31121Big Foot Road
Jackson127.75205.59127206th AvenueExit not signed for this road
131.26211.24131  SD 240 west (Badlands Loop) – Interior, Badlands
143.29230.60143  SD 73 north – PhilipWestern end of SD 73 concurrency
Kadoka150.20241.72150   I-90 Bus. east / SD 73 south – KadokaEastern end of SD 73 concurrency
152.42245.30152  I-90 Bus. west (South Creek Road) – Kadoka
Belvidere163.03262.37163  SD 63 south – BelvidereWestern end of SD 63 concurrency
170.31274.09170  SD 63 north – MidlandEastern end of SD 63 concurrency
172.50277.61172Stamford RoadExit not signed for this road
JonesOkaton177.48285.63177Farm exitExit not signed
Murdo191.14307.61191  I-90 Bus. east – Murdo
192.64310.02192   I-90 Bus. west / US 83 south – Murdo, White RiverWestern end of US 83 concurrency
208.11334.92208CR S10Exit not signed for this road
Lyman212.80342.47212   US 83 north / SD 53 – Pierre, Fort PierreEastern end of US 83 concurrency
220.31354.55220300th AvenueExit not signed for this road
Presho225.38362.71225  I-90 Bus. east – Presho
226.39364.34226   I-90 Bus. west / US 183 south – Presho, Winner
Kennebec235.42378.87235  SD 273 north – Kennebec
Lyman241.90389.30241321st AvenueExit not signed for this road
Reliance248.77400.36248  To SD 47 north – RelianceActual SD 47 route runs parallel to the north along I-90 between exits 248 and 251 and does not connect to this interchange
251.08404.07251  SD 47 south – Gregory, WinnerActual SD 47 route intersects I-90 at this interchange
Oacoma260.47419.19260  I-90 Bus. east (Dougan Avenue) – Oacoma, Chamberlain
Missouri River262.22422.00Lewis and Clark Memorial Bridge over Lake Francis Case
BruleChamberlain263.53424.11263S. Main Street – ChamberlainPartial cloverleaf interchange
265.85427.84265   I-90 Bus. west / SD 50 west – ChamberlainWestern end of SD 50 concurrency
Pukwana272.63438.76272  SD 50 east – PukwanaEastern end of SD 50 concurrency
Kimball284.05457.13284  SD 45 north – KimballWestern end of SD 45 concurrency
289.22465.45289  SD 45 south – PlatteEastern end of SD 45 concurrency
AuroraWhite Lake296.68477.46296White Lake
310.48499.67310  US 281 – Stickney, Aberdeen, Huron
DavisonMount Vernon319.43514.07319Mount Vernon
325.42523.71325Betts Road
Mitchell330.41531.74330   I-90 Bus. east / SD 37 north (S. Ohlman Street) – Mitchell, HuronWestern end of SD 37 concurrency
332.17534.58332   I-90 Bus. west / SD 37 south (S. Burr Street north) – Mitchell, ParkstonEastern end of SD 37 concurrency
Hanson335.42539.81335Riverside Road
Alexandria344.01553.63344  SD 262 east – Fulton, Alexandria
350.05563.35350  SD 25 – Emery, Farmer
McCook353.98569.68353Spencer, Emery
357.99576.13357Bridgewater, Canova
Salem364.01585.82364  US 81 – Salem, Yankton, Madison
MinnehahaHumboldt379.63610.96379  SD 19 – Humboldt, Madison
390.21627.98390  SD 38 – Hartford, Buffalo RidgePartial cloverleaf interchange
Sioux Falls395.46636.43395Marion Road – Sioux FallsPartial cloverleaf interchange
396.52638.14396  I-29 – Fargo, Sioux CitySigned as exits 396A (southbound) and 396B (northbound); cloverleaf interchange; I-29 exits 84A-B
399.54643.00399   SD 115 (Cliff Avenue) – AirportFormer I-90 Business Spur; SPUI
400.58644.67400  I-229 south – Sioux FallsHalf-clover interchange, I-229 exits 10A–B northbound; no access to or from CR 125 (476th Street)
402.55647.84402U.S. Geological Survey, EROS Data CenterFuture northern terminus of SD 100
Brandon406.54654.26406  SD 11 – Corson, Brandon
Valley Springs410.57660.75410Valley Springs, Garretson
412.76664.27  I-90 east – Albert LeaContinuation into Minnesota
1.000 mi = 1.609 km; 1.000 km = 0.621 mi


  1. ^ "Route Log- Main Routes of the Eisenhower National System of Interstate and Defense Highways - Table 1". Federal Highway Administration. Retrieved 4 October 2014.
  2. ^ "South Dakota Codified Laws - § 31-4-184". South Dakota Legislature. Retrieved 2008-06-25.
  3. ^ Jacobs, Travis (August 12, 2017). "Purple Heart Memorial Highway". KIKN. Retrieved June 18, 2018.
  4. ^ Rietman, Diane (December 5, 2002). "Agreement leaves Exit 66 open until next fall". The Rapid City Journal. Retrieved June 8, 2017.
  5. ^ a b Daly, Dan (October 1, 2003). "Exit 66 now road to nowhere". The Rapid City Journal. Retrieved June 8, 2017.
  6. ^ Aust, Scott (September 3, 2004). "Box Elder Officials: Exit 66 land sale pending". The Rapid City Journal. Retrieved June 8, 2017.
  7. ^ "Pavement Condition Monitoring". South Dakota Department of Transportation. Retrieved July 11, 2015.

Route map:

KML is from Wikidata

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