# Missouri Route 21

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 considered dangerous. 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 De Soto 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 | ​ | 0.000 | 0.000 | AR 115 south – Pocahontas | Arkansas state line |
| Ripley | ​ | 8.578 | 13.805 | Route 142 west – Gatewood | Southern end of Route 142 overlap |
| Ripley | ​ | 9.825 | 15.812 | US 160 west – Alton | Southern end of US 160 overlap |
| Ripley | Doniphan | 11.714 | 18.852 | Route 142 east – Business District | Northern end of Route 142 overlap |
| Ripley | ​ | 13.677 | 22.011 | US 160 east – Poplar Bluff | Northern end of US 160 overlap |
| Carter | ​ | 36.031 | 57.986 | US 60 east – Poplar Bluff | Southern end of US 60 overlap |
| Carter | ​ | 45.608 | 73.399 | US 60 west / Route 34 begins – Van Buren | Northern end of US 60 overlap; Southern end of Route 34 overlap |
| Reynolds | ​ | 48.959 | 78.792 | Route 34 east – Clearwater Dam, Piedmont | Northern end of Route 34 overlap |
| Reynolds | Ellington | 65.112 | 104.788 | Route 106 west – Owls Bend, Eminence, Business District | |
| Reynolds | ​ | 77.088 | 124.061 | Route 72 west – Bunker | Southern end of Route 72 overlap |
| Reynolds | ​ | 85.027 | 136.838 | Route 49 north – Black, Oates | Southern end of Route 49 overlap |
| Iron | ​ | 98.252 | 158.121 | Route 49 south – Annapolis | Northern end of Route 49 overlap |
| Iron | Arcadia | 107.967 | 173.756 | Route 72 east | Northern end of Route 72 overlap |
| Iron | Pilot Knob | 110.072 | 177.144 | Route 221 north | |
| Iron | ​ | 119.405 | 192.164 | Route 32 west | Southern end of Route 32 overlap |
| Washington | Caledonia | 123.672 | 199.031 | Route 32 east – Bismarck | Northern end of Route 32 overlap |
| Washington | Potosi | 135.913 | 218.731 | Route 8 – Potosi, Leadwood | |
| Washington | Old Mines | 142.085 | 228.664 | Route 47 south – Bonne Terre | Southern end of Route 47 overlap |
| Washington | ​ | 147.011 | 236.591 | Route 47 north – Richwoods | Northern end of Route 47 overlap |
| Washington | Washington State Park | 149.523 | 240.634 | Route 104 east | |
| Washington | Washington State Park | 150.912 | 242.869 | Route 104 west | |
| Jefferson | ​ | 161.379 | 259.714 | Route 110 east | |
| Jefferson | Hillsboro | 165.177 | 265.827 | Route B begins / Business 21 | Southern end of Route B overlap |
| Jefferson | ​ | 165.547 | 266.422 | Route B north | Northern end of Route B overlap; southern end of freeway |
| Jefferson | Hillsboro | 167.854 | 270.135 | Route A / Business 21 | |
| Jefferson | ​ | 169.236 | 272.359 | Hayden Road | |
| Jefferson | ​ | 172.575 | 277.733 | Old Route 21 - Goldman | |
| Jefferson | ​ | 175.162 | 281.896 | Old Route 21 / Schenk Road | |
| Jefferson | Otto | 177.733 | 286.034 | Route MM / Route M – House Springs, Barnhart | |
| Jefferson | ​ | 180.341 | 290.231 | Old Route 21 - Shady Valley | |
| Jefferson | ​ | 184.555 | 297.012 | Old Route 21 - Meramec Heights | Southbound exit and northbound entrance |
| Jefferson | ​ | 185.469 | 298.483 | Route 141 – Fenton, Arnold | Interchange; northern end of freeway |
| Jefferson | ​ | 185.864 | 299.119 | Meramec Bottom Road | |
| St. Louis | Concord | 190.517 | 306.607 | I-270 – Chicago, Memphis | I-270 exit 2 |
| St. Louis | Concord | 191.717 | 308.539 | US 50 / US 61 / US 67 (Lindbergh Boulevard) | |
| St. Louis | Affton | 194.126 | 312.416 | Route 30 (Gravois Road) | |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Incomplete access ||||||

## Hillsboro Business Spur

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.