San Bernardino National Forest is a federally managed forest encompassing 823,816 acres. The forest is made up of two main divisions, the San Bernardino Mountains on the easternmost of the Transverse Ranges, and the San Jacinto and Santa Rosa Mountains on the northernmost of the Peninsular Ranges. Elevations range from 2,000 to 11,499 feet (600 to 3505 m).
The forest includes five wilderness areas: San Gorgonio, Cucamonga, San Jacinto, Santa Rosa and Bighorn Mountain. Forest headquarters are located in the city of San Bernardino on the edge of California's Inland Empire region. There are district offices in Fontana, Idyllwild, and Skyforest.
Free camping is available at 11 different 'Yellow Post' campsites year round.
There are many different species of trees, many coniferous, that grow in the mountains. Pines, such as ponderosa pine, Jeffrey pine, sugar pine, Coulter pine, lodgepole pine, single-leaf pinyon, and knobcone pine all thrive here. Other coniferous trees, such as white fir, bigcone Douglas-fir (Pseudotsuga macrocarpa), incense cedar, and western juniper also thrive here. Canyon live oak, California black oak, and Pacific dogwood are other trees that also grow here. The forest contains an estimated 87,400 acres (354 km2) of old growth.