Prairie Rose State Park West Campground

Yosemite National Park ( yoh-SEM-ih-tee) is a national park of the United States in California. It is bordered on the southeast by the Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers 1,187 mi2 (3,070 km2) in four counties – centered in Tuolumne and Mariposa, extending north and east to Mono and south to Madera. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its granite cliffs, waterfalls, clear streams, groves of giant sequoia, lakes, mountains, meadows, glaciers, and biological diversity. Almost 95 percent of the park is designated wilderness. Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada mountain range.

Its geology is characterized by granite and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and tilted to form its unique slopes, which increased the steepness of stream and river beds, forming deep, narrow canyons. About one million years ago, glaciers formed at higher elevations. They moved downslope, cutting and sculpting the U-shaped Yosemite Valley.

Humans may have first entered the area 10,000 to 8,000 years ago, with Native Americans having inhabited the region for nearly 4,000 years. European Americans entered the area by 1833. The best documentated first entrance of European Americans into Yosemite Valley occurred when the Mariposa Battalion, commissioned by Governor McDougal and led by James D. Savage, attacked the Ahwahneechee there in 1851.

Yosemite was critical to the development of the concept of national parks. Galen Clark and others lobbied to protect Yosemite Valley from development, ultimately leading to President Abraham Lincoln's signing of the Yosemite Grant of 1864 that declared Yosemite as federally preserved land. In 1890, environmentalist John Muir led a successful movement to motivate Congress to establish Yosemite Valley and its surrounding areas as a National Park. This helped pave the way for the National Park System. Yosemite draws about four million visitors annually. Most visitors spend the majority of their time in the valley's seven square miles (18 km2). The park set a visitation record in 2016, surpassing five million visitors for the first time. In 2024, the park received over four million visitors.