Balanced Rock, 128 ft (39m) high, with the balancing rock rising 55 feet (16.75m) above the base. The big rock on top is the size of three school buses. Arches National Park, 76,679 acres (31,031 ha); preserves over 2,000 natural sandstone arches. National Monument est. 1929; National Park 11/12/1971. Grand County, UT.