U.S. Federal Route 20 is a east-west highway in Northern Woodbury County. From east of Moville to the Iowa/Nebraska State Line, it is a multi-lane highway. U.S. Rt. 20 passes through the following towns in Woodbury County. Correctionville Lawton Sioux City U.S. Rt. 20 is multi-plexed in Woodbury County. U.S. Rt. 75, at Sioux City.