| State: | MO |
| Type: | MO |
| Route: | 18 |
| Map Custom: | yes |
| Maint: | MoDOT |
| Length Mi: | 55.88 |
| Direction A: | West |
| Direction B: | East |
| Terminus A: | 359th Street / State Line Road at the Kansas state line in Drexel |
| Junction: | in Adrian |
| Terminus B: | in Clinton |
| Previous Type: | MO |
| Previous Route: | 17 |
| Next Type: | MO |
| Next Route: | 19 |
Route 18 is a highway in western Missouri. Its eastern terminus is at the intersection of Route 13/Route 52 and Route 7 in Clinton. Its western terminus is at the Kansas state line near Drexel. It continues into Kansas as a county road.
Route 18 begins at the Kansas state line just west of Drexel. It runs for three miles (5 km) along the Cass/Bates County line. Route 18 then turns south to Merwin, where it turns back east. It then runs through Adrian, before having a diamond interchange with the Interstate 49/U.S. Route 71 freeway.[1] Route 18 then runs south of Altona and through Ballard. It then runs through Clinton. Route 18 then ends at Routes 7, 13, and 52.