It begins at Interstate 29 near Mondamin and ends in Logan at U.S. Highway 30 (US 30).

Just east of I-29, it meets Harrison County Road K45 (CR K45), which is a former alignment of US 75.

Three miles (4.8 km) east of Mondamin, it meets the southern end of Iowa Highway 183, which is part of the Loess Hills Scenic Byway (LHSB).

The route travels east for 6 miles (9.7 km),[2] passing through Magnolia, after which it turns to the south towards Logan.

[3] Iowa Highway 127 originally went traveled between US 75 west of Magnolia, where it now meets Harrison CR L20, and US 30 in Logan.