State Route 173 is a major east–west thoroughfare completely within Salt Lake County in northern Utah.

From its western terminus at SR-111 it passes through the growing west side of Salt Lake County, eventually reaching US-89 in Murray.

Shortly thereafter, the route crosses under I-215 and passes Taylorsville High School at the Redwood Road (SR-68) continuous flow intersection.

The route continues eastward, crossing a canal before descending a steep hill to the Jordan River as it enters Murray and shifts slightly to the north (taking the name 5300 South).

East of its single-point urban interchange with I-15, the route passes under the Union Pacific, UTA's FrontRunner, and TRAX (Blue and Red) rail lines as they run close together at the approach to Murray Central station, and Cottonwood Street passes over the TRAX line and SR-173 simultaneously on a high viaduct.