U.S. Federal Route 31 is a north-south highway in Central Clark County. It runs from the Clark/Scott County Line to the Kentucky/Indiana State Line. U.S. Rt. 31 passes thorugh the following towns in Clark County. Underwood Henryville Memphis Speed Sellersburg Clarksville Jeffersonville U.S. Rt. 31 is multi-plexed in Clark County. Interstate 65, from Clarksville to Jeffersonville.