Missouri Route 21

Route 21
Tesson Ferry Road
Route information
Maintained by MoDOT
Length:	188 mi (303 km)
Existed:	1922 – present
Major junctions
South end:	Highway 115 at the Arkansas state line
	US 160 in Doniphan US 60 near Van Buren Route 72 in Centreville Route 49 in Hogan Route 32 in Caledonia Route 47 in Mineral Point Route M/Route MM in Barnhart Route 141 in Paulina Hills Interstate 270 Lindbergh Boulevard
North end:	Route 30 in Affton
Location
Counties:	Ripley, Carter, Reynolds, Iron, Washington, Jefferson, St. Louis
Highway system
Missouri Highways Supplemental ← Route 20 Route 22 →

Route 21 is a highway in eastern Missouri. Its northern terminus is at Route 30 in Affton. Its southern terminus is at the Arkansas state line (where it continues as Highway 115). In the St. Louis area, it is known as Tesson Ferry Road, which was named after the 19th century proprietor of the ferry across the Meramec River.

The section through northern Jefferson County, Missouri was the site of numerous fatal traffic accidents due to the narrow road being unable to handle increased traffic from "population growth", and was referred to as "Blood Alley" and "Missouri's Most Dangerous Highway" (and was featured in an Reader's Digest article on dangerous roads)^{[citation needed]}. As a result, the road was rerouted and built to freeway standards. Construction to reroute the highway to just south of Hillsboro was completed on December 15, 2008 and Route 21 is currently freeway standard from Route 141 to Highway B. Plans to extend the freeway south to DeSoto have been approved, but funds are lacking to complete this part of the project.

Route 21 from the Meramec River to Route B, along with Route M, make up the Jefferson County Scenic Byway.

Exit list

Exits are not numbered.

County	Location	Mile	Destinations	Notes
Southern end of freeway. Road continues south as 2 lane highway.
Jefferson	Hillsboro	165	Route 21 south / Route B – Cedar Hill, DeSoto	Southbound exit and northbound entrance All traffic must exit
		167	Route A – Festus, Hillsboro
		169	Hayden Road, Jefferson College
		172	Old Route 21, Goldman
		175	Old Route 21, Schenk Road
	House Springs	177	Route M / Route MM – Barnhart, House Springs
		180	Old Route 21, Shady Valley
	Arnold	184	Old Route 21, Meramec Heights	Southbound exit and northbound entrance
		185	Route 141 – Arnold, Fenton
Northern end of freeway. Road continues north as Tesson Ferry Road.

Hillsboro Business Spur

Route 21 Business
Location:	Hillsboro, Jefferson County

Business 21 follows the old alignment of Route 21 through the city of Hillsboro. It begins at the intersection of Route 21 and Highway B on the southern edge of the city, and continues north to the intersection of Route A and Old Route 21, where it ends. Business 21 is the only way one can now reach Route BB, as the rerouting of Route 21 bypasses the road.