The International Selkirk Loop is a 280-mile-long (450 km) scenic highway in the U.S. states of Idaho and Washington, as well as the Canadian province of British Columbia. The loop encircles the Selkirk Mountain Range, and offers several side trips aside from the main route. Included on the loop is the Kootenay Lake Ferry, the longest free ferry in the world. The portion of the loop in the United States has been designated an All-American Road by the United States Department of Transportation.

The Selkirk Mountains are a mountain range spanning the northern portion of the Idaho Panhandle, eastern Washington, and southeastern British Columbia which are part of a larger grouping of mountains, the Columbia Mountains. They begin at Mica Peak and Krell Hill near Spokane and extend approximately 320 km north from the border to Kinbasket Lake, at the now-deserted location of the onetime fur company post, Boat Encampment. The range is bounded on its west, northeast and at its northern extremity by the Columbia River, or the reservoir lakes now filling most of that river's course. From the Columbia's confluence with the Beaver River, they are bounded on their east by the Purcell Trench, which contains the Beaver River, Duncan River, Duncan Lake, Kootenay Lake and the Kootenay River. The Selkirks are distinct from, and geologically older than, the Rocky Mountains. The neighboring Monashee and Purcell Mountains, and sometimes including the Cariboo Mountains to the northwest, are also part of the larger grouping of mountains known as the Columbia Mountains. A scenic highway loop, the International Selkirk Loop, encircles the southern portions of the mountain range.