State Route 27 (SR 27) is a 90-mile-long (145 km) state highway serving Whitman and Spokane counties, located in the eastern region of the U.S. state of Washington. The highway travels generally north from U.S. Route 195 (US 195) through Pullman, Palouse, Tekoa, and Spokane Valley to SR 290 north of an interchange with Interstate 90 (I-90). SR 27 serves the Palouse region as part of the Palouse Scenic Byway and travels between US 195 to the west and US 95 to the east in Idaho, with several auxiliary routes connecting to the two other highways.

Whitman County is a county located in the U.S. state of Washington. As of the 2020 census, the population was 47,973. The county seat is Colfax, and its largest city is Pullman.