The John Muir Wilderness is a wilderness area that extends along the crest of the Sierra Nevada of California for 90 miles, in the Inyo and Sierra National Forests. Established in 1964 by the Wilderness Act and named for naturalist John Muir, it encompasses 652,793 acres. The wilderness lies along the eastern escarpment of the Sierra from near Mammoth Lakes and Devils Postpile National Monument in the north, to Cottonwood Pass near Mount Whitney in the south.