The Sierra Nevada constitute the longest mountain range in the United States and contain the highest peaks in the contiguous 48 states.
The Sierra is a "fault block" range, rising out of the desert to the east in a steep escarpment, then sloping gently toward the Central Valley on the west. Its granite is part of much older batholiths. Precipitation comes inland from the Pacific, falls as snow or rain on the mountains, then flows back to the sea.
The northerly part of the range, north of Donner Pass, is the tamest. Roads thread much of the area and there are numerous year-round communities. The central part of the Sierra from Donner Pass to Sonora, is higher and rougher. The southern part, from Sonora Pass to Tehachapi Pass is the highest. Some of the peaks were never covered by ice, so the rocks date back to the ocean bed. The most spectacular parts are protected in Sequoia National Park and Kings Canyon National Park.