Yosemite National Park

Yosemite National Park is located in the central Sierra Nevada of California and lies 150 miles east of San Francisco and only a six hour drive from Los Angeles. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its spectacular granite cliffs, waterfalls, clear streams, giant sequoia groves, and biological diversity. The 750,000-acre, 1,200 square-mile park contains thousands of lakes and ponds, 1600 miles of streams, 800 miles of hiking trails, and 350 miles of roads. Two federally designated wild and scenic rivers, the Merced and Tuolumne, begin within Yosemite’s borders and flow west into California's Central Valley. Annual park visitation exceeds 3.5 million, with most visitor use concentrated in the seven square mile area of Yosemite Valley.

The geology of Yosemite is characterized by granitic rocks and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and then tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, narrow canyons. About 1 million years ago, snow and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet during the early glacial episode. The downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today.