Pend Oreille
At Colville, SR 20 turns east away from US 395 and continues into the southern reaches of the Selkirk Mountains. The highway forms the northern boundary of the Little Pend Oreille National Wildlife Refuge and follows the Little Pend Oreille River north through a series of glacial lakes. After entering Pend Oreille County, SR 20 makes a series of hairpin turns to descend into the Pend Oreille Valley. At an intersection with SR 31 in Tiger, the highway turns south to follow the Pend Oreille River, becoming part of the International Selkirk Loop and Pend Oreille Scenic Byway in the process. SR 20 continues south along the river, joined by the Pend Oreille Valley Railroad, and intersects SR 211 at Usk. Approximately southeast of Usk, the highway terminates at US 2, just west of the Washington–Idaho state line.