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 State Highway System Interstate US State Supplemental ← x20px 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). 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.

Major intersections

County	Location	mi	km	Destinations	Notes
Ripley	​			AR 115 south – Pocahontas	Arkansas state line
	​			Route 142 west – Gatewood	Southern end of Route 142 overlap
	​			US 160 west – Alton	Southern end of US 160 overlap
	Doniphan			Route 142 east – Business District	Northern end of Route 142 overlap
	​			US 160 east – Poplar Bluff	Northern end of US 160 overlap
Carter	​			US 60 east – Poplar Bluff	Southern end of US 60 overlap
	​			US 60 west – Van Buren	Northern end of US 60 overlap; Southern end of Route 34 overlap
Reynolds	​			Route 34 east – Clearwater Dam, Piedmont	Northern end of Route 34 overlap
	Ellington			Route 106 west – Owls Bend, Eminence, Business District
	​			Route 72 west – Bunker	Southern end of Route 72 overlap
	​			Route 49 north – Black, Oates	Southern end of Route 49 overlap
Iron	​			Route 49 south – Annapolis	Northern end of Route 49 overlap
	Arcadia			Route 72 east	Northern end of Route 72 overlap
	Pilot Knob			Route 221 north
	​			Route 32 west	Southern end of Route 32 overlap
Washington	Caledonia			Route 32 east – Bismarck	Northern end of Route 32 overlap
	Potosi			Route 8 – Potosi, Leadwood
	Old Mines			Route 47 south – Bonne Terre	Southern end of Route 47 overlap
	​			Route 47 north – Richwoods	Northern end of Route 47 overlap
Jefferson	​			Route 110 east
	Hillsboro			Business 21	Southern end of Route B overlap
	​	165	266	Route B north	Northern end of Route B overlap; southern end of freeway
	Hillsboro	167	269	Route A
	​	169	272	Hayden Road
	​	172	277	Old Route 21 - Goldman
	​	175	282	Old Route 21 / Schenk Road
	​	177	285	Route MM / Route M – House Springs, Barnhart
	​	180	290	Old Route 21 - Shady Valley
	​	184	296	Old Route 21 - Meramec Heights	Southbound exit and northbound entrance
	​	185	298	Route 141 – Fenton, Arnold
St. Louis	​			Meramec Bottom Road	Interchange; northern end of freeway
	Concord			I-270 – Chicago, Memphis	I-270 exit 2
				US 50 / US 61 / US 67 (Lindbergh Boulevard)
	Affton			Route 30 (Gravois Road)
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Incomplete access

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.