Organ Pipe Cactus National Monument is a
U.S. National Monument and
UNESCO biosphere reserve located in extreme southern
Arizona which shares a border with the
Mexican state of
Sonora. The park is the only place in the
United States where the
Organ Pipe Cactus grows wild. Along with Organ Pipe, many other types of
cacti, as well as other desert flora native to the
Yuma Desert section of the
Sonoran Desert region grow here. The Park is a beautiful preservation of the
American Southwest. Organ Pipe Cactus National Monument is 517 square miles (1,338 square kilometers) in size. In 1976 the monument was declared a Biosphere Reserve by UNESCO, and in 1977 95% of Organ Pipe Cactus was declared a wilderness area.