Yosemite National Park is a US national park located in California's western Sierra Nevada. The park is 747,956 acres in size and is overseen by the US National Park Service. In 1984, Yosemite National Park was recognized as a UNESCO World Heritage Site for its granite cliffs, waterfalls, clear streams, massive sequoia groves, lakes, mountains, meadows, glaciers, and ecological diversity. Almost the whole of the park has been declared wilderness.