Missouri Route 51
Route 51 is a highway in southeastern Missouri. Its northern terminus is the Illinois state line near Chester, Illinois; its southern terminus is at the Arkansas state line northwest of Piggott, Arkansas. It continues into Illinois as Illinois [Route 150] and it continues into Arkansas as Highway 139.
Route 51 is one of the original 1922 state highways and ran from the Mississippi River to Advance.
Route 51A, a branch route, formerly connected Route 51 with Puxico when Route 51 ended at Advance. Route 51A would become part of the main highway when it was re-routed and extended.