The Sierra Nevada (Spanish: [ˈsjera neˈβaða], snowy mountain range) is a mountain range in the U.S. states of California and Nevada, between the California Central Valley and the Basin and Range Province. The Sierra runs 400 miles (640 km) north-to-south, and is approximately 70 miles (110 km) across east-to-west. Notable Sierra features include Lake Tahoe, the largest alpine lake in North America; Mount Whitney at 14,505 ft (4,421 m), the highest point in the contiguous United States; and Yosemite Valley sculpted by glaciers out of 100-million-year-old granite. The Sierra is home to three national parks, 20 wilderness areas, and two national monuments. These areas include Yosemite, Sequoia and Kings Canyon National Parks.

The character of the range is shaped by its geology and ecology. More than 100 Ma (million years ago), granite formed deep underground. The range started to uplift 4 Ma, and erosion by glaciers exposed the granite and formed the light-colored mountains and cliffs that make up the range. The uplift caused a wide range of elevations and climates in the Sierra, which are reflected by the presence of five life zones.