Sierra National Forest is a U.S. National Forest located on the western slope of central Sierra Nevada in the state of California. The forest is known for its mountain scenery and natural resources. Forest headquarters are located in Clovis, California. There are local ranger district offices in North Fork and Prather. The forest's boundary starts clockwise at the intersections of the Merced River, The Sweetwater Creek and the HWY 140 then moves east following the Merced River canyon to the border with the Yosemite National Park near El Portal. Then it follows the parks southern boundary till it reaches the Inyo National forest near Electra Peak. From there it travels south to its border with the Kings Canyon National Park near Mt Goethe.
It then follows the park's northern border, then heads south to the Kings River near Deer Canyon. From there it moves down the Kings River canyon east; south of the river is the Sequoia National Forest. When it reaches Pine Flat Lake near Trimmer, it turns north towards Tollhouse and continues on to Auberry. From there the NF moves on to North Fork, then west to form a small finger towards Coarsegold. Finally, the boundary travels north to Yosemite Forks and moves west towards Miami Mountain, then heads north to return to the Merced River.
Sierra covers in descending order of forestland area, the eastern portions of Fresno, Madera, and Mariposa counties, adjacent to the southern part of Yosemite National Park. It includes more than 1,300,000 acres (2,000 sq mi; 5,300 km2), at altitudes ranging from 900 to 13,986 feet (274 to 4,263 m) in elevation. The terrain includes rolling, oak-covered foothills, heavily forested middle elevation slopes and the Alpine landscape of the High Sierra.
The forest includes a number of scenic attractions, including Fresno Dome and Nelder Grove. Several reservoirs offer fishing, including Bass Lake, Wishon Reservoir, and Courtright Reservoir. Also, there are numerous hiking opportunities in wilderness areas: Ansel Adams, John Muir, Dinkey Lakes, Kaiser, and Monarch. It also has a ski area, Sierra Summit Ski Area, that operates under a special use permit.
The ecology of the National Forest are typical for the western side of the southern Sierra Nevada: distributions of species are largely governed by climate, which is strongly dependent on altitude. The ecology can be described by biotic zones, which are marked by either a tree indicator species, or by a lack of trees. The biotic zones include the foothill Woodland zone from 1,000 to 3,000 feet (300 to 910 m) (interior live oak), the lower montane zone from 3,000 to 7,000 feet (910 to 2,100 m) (Yellow pine), the upper montane zone from 7,000 to 9,000 feet (2,100 to 2,700 m) (Lodgepole pine/Red fir), the subalpine zone from 9,000 to 9,500 feet (2,700 to 2,900 m) (Whitebark pine), and the alpine zone from 9,500 feet (2,900 m) (above the tree line).
In addition, some 383,000 acres (598 sq mi; 1,550 km2) of the forest are old growth, containing Lodgepole Pine (Pinus contorta), Red Fir (Abies magnifica).