South of the community of Shaniko, US 97 forks off its only spur route, U.S. Route 197 which continues heading parallel to the Deschutes River towards Tygh Valley and The Dalles. Route 97 takes a more easterly course, passing through the high desert region of the Columbia Plateau. Towns along the route include Grass Valley and Wasco. Just south of Biggs Junction, the highway descends from the plateau into the Columbia River Gorge. In Biggs is an interchange with Interstate 84 and U.S. Route 30; immediately north of the interchange is the Biggs Rapids-Sam Hill Bridge over the Columbia River. The river serves as the state line between Oregon and Washington. Work on US 97 near Biggs in 1966 led to the discovery of the Biggs jasper, a sought-after gemstone.