Size: 130,790 acres
Year Designated: 1978
Fast Fact: Hawaii Volcanoes Wilderness includes Mauna Loa, the Earth’s largest volcano.
Encompassing 130,790 acres and the world’s largest active volcano, the Hawaii Volcanoes Wilderness protects a unique ecosystem in the United States: that of a still-forming island. Visitors to the area can observe almost all aspects of the volcano, from lava fields and vents (kept a certain distance away from paths, in order to limit exposure to potentially noxious fumes) to magma entering the Pacific Ocean.