Route 145 is a short highway in Mercer County, Missouri. Its northern terminus is at Route B; its southern terminus is at U.S. Route 136. There are no towns on the route.

Route 145 begins at an intersection with US 136 west of Princeton, heading north on a two-lane undivided road. The route passes through agricultural areas with some trees, curving northwest and running to the east of Lake Paho. The road heads west and crosses the lake, continuing through more rural areas. Route 145 comes to its northern terminus at an intersection with Route B.

The entire route is in Princeton, Mercer County.