| Salmon–Challis National Forest | |
| Map: | USA |
| Relief: | 1 |
| Location: | Idaho, United States |
| Nearest City: | Salmon, Idaho |
| Coordinates: | 45.2817°N -114.1958°W |
| Area Acre: | 4,235,940 |
| Established: | July 1, 1908 |
| Governing Body: | U.S. Forest Service |
| Website: | Salmon-Challis National Forest |
Salmon–Challis National Forest is located in east central sections of the U.S. state of Idaho. At 4,235,940 acres (6,618.66 sq mi, or 17,142.24 km2) it is one of the largest national forests in the lower 48 states and also has most of the land area of the Frank Church–River of No Return Wilderness, which is the largest wilderness area south of Alaska.
Borah Peak, the tallest mountain in Idaho, is also found here. The Wild and Scenic designated Salmon River weaves through the rugged terrain of the Sawtooth Mountains and Sawtooth National Recreation Area, while it flows for over 75miles through the forest. The Big Lost River has its headwaters within the national forest.
Challis National Forest, the more southerly of its two parts, lies primarily in Custer County, but also has major areas in Lemhi and Butte counties, as well as smaller areas in Clark and Blaine counties. It has a total area of 2,463,471 acres (3,849.17 sq mi, or 9,969.31 km2). There are local ranger district offices located in Challis, Clayton, and Mackay.
Salmon National Forest, which lies to the north, is primarily located in Lemhi County, with spillover into Valley and Idaho counties. It has a total area of 1,772,469 acres (2,769.48 sq mi, or 7,172.93 km2).[1] There are local ranger district offices located in Leadore, North Fork, and Salmon.
The combined forest headquarters are located in Salmon, Idaho.
There is a weather station at Middle Fork Lodge, which is on the western edge of Salmon–Challis National Forest.
There are two officially designated wilderness areas within Salmon–Challis National Forest that are part of the National Wilderness Preservation System. Both extend into neighboring National Forests or onto lands of the Bureau of Land Management.