U.S. Route 31 (US 31) is a part of the United States Numbered Highway System that runs from Spanish Fort, Alabama, to Mackinaw City, Michigan. In the U.S. state of Tennessee, it runs concurrently with Interstate 65 (I-65) for the first mile northward from the Tennessee state line. There US 31 parallels I-65 to downtown Nashville. At Pulaski US 31 meets the southern terminus of US 31A in Tennessee. US 31 continues due north through Lynnville, Columbia, Spring Hill, Franklin and Brentwood to Nashville. The route splits into US 31E and US 31W in Nashville and go into Kentucky.