[5] The entire length of the Selway was included by the United States Congress in 1968 as part of the National Wild and Scenic Rivers Act.

[6] The main stem of the Selway is 100 miles (160 km) in length[3] from the headwaters in the Bitterroots to the confluence with the Lochsa near Lowell to form the Middle Fork of the Clearwater.

The Selway River drains a 2,013-square-mile (5,210 km2) basin in Idaho County.

Four salmon channels were built "in the mid-1960s by the Idaho Department of Fish and Game and by the Job Corps ... along the Selway to help re-establish the spring chinook run after hydroelectric dams were built downstream."

The river was stocked with salmon eggs and fry "each fall through 1981, and again in 1985.