The main highways in the county are U.S. Route 63, which cuts through the southwestern corner and passes through Koshkonong and Thayer, and U.S. Route 160, which runs from west to east through Alton and the central part of the county. Other roads include Missouri State Highways 19, which passes northeast to southwest through Alton and Thayer, 99, whose southern terminus is at U.S. Route 160 west of Alton, and 142, which runs through the southernmost part of the county and crosses U.S. Route 63 at Thayer. | The main highways in the county are U.S. Route 63, which cuts through the southwestern corner and passes through Koshkonong and Thayer, and U.S. Route 160, which runs from west to east through Alton and the central part of the county. Other roads include Missouri State Highways 19, which passes northeast to southwest through Alton and Thayer, 99, whose southern terminus is at U.S. Route 160 west of Alton, and 142, which runs through the southernmost part of the county and crosses U.S. Route 63 at Thayer. |