Merced River overflows as vernal falls during heavy spring snowmelt. Yosemite National Park (est. 1906), 761,268 acres (3,080.74 km2), 1,189 sq mi (3,080 km2). Park elevations range from 2,127 to 13,114 feet (648 to 3,997 m) and contains five major vegetation zones: chaparral/oak woodland, lower montane, upper montane, subalpine, and alpine. Yosemite Valley carved by glacial movement about 1 million years ago. World Heritage Site (1984). Mariposa County, CA.