It begins at U.S. Highway 20 (US 20) southwest of Masonville and ends at Iowa 150 south of Fayette.

Further west, it will turn to the north where it will terminate at an intersection with Iowa 150 south of Fayette.

Originally, the highway began at an intersection with US 20 four miles (6.4 km) east of Winthrop.

Just north of Lamont, the highway curved to the east and crossed into Delaware County.

Shortly thereafter, the highway ended at the western gate of Backbone State Park.