Its western terminus is at the Kansas state line near Drexel.

Route 18 begins at the Kansas state line just west of Drexel.

It runs for three miles (5 km) along the Cass/Bates County line.

It then runs through Adrian, before having a diamond interchange with the Interstate 49/U.S.

[1] Route 18 then runs south of Altona and through Ballard.