Havasu Wilderness is a protected 17,801-acre area within the Havasu National Wildlife Refuge near Lake Havasu, spanning Arizona and California. Its terrain combines sharply contrasting desert and river environments, including volcanic spires, a large sand dune, wetlands, open water, Mojave Desert uplands, dry mountains, and washes. Vegetation ranges from creosote bush, ocotillo, blue-green paloverde, and saguaro to trees in the washes and willows and salt cedar along the river. The area is especially important for wildlife, supporting many birds, desert bighorn sheep, coyote, bobcat, Gila monster, and endangered species such as the Yuma rail and desert tortoise. Strict limits on use help protect these habitats.