U.S. Route 431, is an urge of U.S. Route 31. It presently runs for 556 miles from Owensboro, Kentucky at U.S. Route 60 to Dothan, Alabama at U.S. Route 231 & U.S. Route 84. Through more parts of US 431 it is a 2 lane with not more places of it being a 4 lane highway.