Ohio State Route 173 is an arrow-straight east-west route in eastern Ohio. It runs in Stark and Columbiana Counties, passing through Alliance to reach Salem. The western end is just north of Louisville, Ohio, at Ohio Route 44. From there, Ohio Route 173 runs east to skewer right through Alliance, where it is joined by US Route 62. US Route 62 stays concurrent with Ohio Route 173 for most of its length. A bypass shaped like the letter "C" wraps around Salem, save for the east side of town. As Ohio Route 173 meets the bypass coming from the west, US Route 62 leaves Ohio Route 173 to join the bypass northward. Ohio Route 173 runs easterly right into the center of Salem, where it ends at Ohio Routes 9 and 14.