U.S. Route 40 in Missouri

U.S. Route 40 marker
U.S. Route 40
Map
US 40 highlighted in red
Route information
Maintained by MoDOT
Existed1926–present
Major junctions
West end I-70 / US-24 / US-40 / US-169 in Kansas City
Major intersections
East end I-55 / I-64 / US 40 in St. Louis
Location
CountryUnited States
StateMissouri
CountiesJackson, Lafayette, Saline, Cooper, Howard, Boone, Callaway, Montgomery, Warren, St. Charles, St. Louis, City of St. Louis
Highway system
Route 39 Route 41

U.S. Route 40 (US 40) in the state of Missouri is a U.S. highway that runs from Kansas City to St. Louis. Outside of Greater St. Louis, much of the route either parallels or runs along I-70. East of Wentzville in Greater St. Louis, the route runs along I-64.