The range exceeds 120 miles (190 km) in length and its boundaries are usually defined by the Salmon River and its large tributary forks.

Part of the central Rocky Mountains, the entire range lies west of the continental divide and drains to the Snake River.

The highest peak is White Mountain, at 10,442 feet (3,183 m) above sea level; five peaks have summits exceeding 10,000 feet (3,050 m), and the three major subranges are defined by other forks of the Salmon River: the West, Central, and East Salmon River Mountains.

Although the northwestern corner of the range is only about thirty miles (50 km) southeast of the river port of Lewiston, the Salmon River Mountains occupy one of the remotest areas in the contiguous United States.

[2] The height of the mountains gradually increases from west to east, sloping up towards the continental divide along the border with Montana.