State Route 174 (SR 174) is a state highway in the U.S. state of California. The two-lane 13-mile (21 km) highway, added to the state highway system in 1933, connects Interstate 80 in Colfax with SR 20/SR 49 in Grass Valley, crossing the Bear River next to a 1924 concrete arch bridge. The majority of the highway is eligible for the State Scenic Highway System, but local residents have blocked its designation due to property rights concerns.