The Missouri Department of Transportation closed Missouri Highway 79 south of Hannibal due to water over the road.
The road is closed just south of the entrances to Sawyer's Creek and the Mark Twain Cave.
Southbound motorists should detour over routes T and N to Missouri Highway 79.
Commercial vehicles must use U.S. 61 to Business 61 and Route V in New London, then proceed on routes T and N back to Missouri Highway 79.
Detour signs and message boards are in place to advise motorists of the road closure and alternate routes.