Size: 217,000 acres
Year Designated: 1972
Fast Fact: Sawtooth Wilderness, according to the EPA, has some of the cleanest air in the lower 48 states.
The Sawtooth Wilderness is a world of jagged peaks—hundreds of them, with 50 measuring over 10,000 feet in elevation. The area also encompasses nearly 400 alpine lakes, as well as the headwaters of three major rivers: the Boise River, the Payette River and the Salmon River. Designated as a Mandatory Class I air quality area, which heavily regulates the amount of emitted particulates allowed in the air, Sawtooth Wilderness boasts the cleanest air in the continental United States.