High Quality Content by WIKIPEDIA articles! U.S. Route 431 is a spur of U.S. Route 31. It currently runs for 556 miles (895 km) from Owensboro, Kentucky at U.S. Route 60 to Dothan, Alabama, at U.S. Route 231 and U.S. Route 84. Through many parts of US 431 it is a two lane with not many places of it being a four lane highway.