Organ Pipe Cactus National Monument
Prehistoric desert people wandered the upland canyons of the Ajo Range to gather wild foods and to drink from pools of water in the rock known as tinajas. When the Spanish arrived in the 16th century, descendants of these prehistoric peoples, the Tohono O'odham (formerly called the Papago), occupied this section of the Sonoran Desert and were engaged in dry farming. As late as 1929, the area was occupied by a community of Tohono O’odham, whose buildings covered about two hundred acres, and included a ballcourt and pithouse and other activity clusters.
Exploration & Settlement
During the three centuries after the arrival of the Spanish, the natural habitat was greatly disturbed by cattle ranching and mining of the desert for precious metals. But since its establishment as a national monument, this unique region of the Sonoran area has begun to revert to its wilderness state.
The monument was established April 12, 1937, by Presidential Proclamation of Franklin D. Roosevelt. Established as an International Biosphere Reserve in 1976 by the United Nations, it is an almost pristine example of the Sonoran Desert. In 1978 Quitobaquito Springs was placed on the National Register of Historic Places. In 2001 Organ Pipe Cactus National Monument (specifically Quitobaquito Springs) and nearby Cabeza Prieta National Wildlife Refuge were declared Globally Important Bird Areas (IBA) by the American Bird Conservancy.
Elevation 1670 ft. at the visitor center; highest elevation 4808 ft. at Mt. Ajo.
Average Precipitation 7.2 inches
Acreage: 330,689 acres, with 95% designated wilderness
- Federal: 329,316.31
- Non-federal: 1,372.55
- Wilderness area: 312,600
Plants & Animals
Organ Pipe Cactus National Monument was established to protect the rare organ pipe cactus and 27 other cacti species, as well as 550 species of vascular plants, and more than 200 species of birds and other animals, many of which are unique to this area. Three distinctive divisions of the Sonoran Desert converge here, representing six plant communities. The uniqueness of this habitat is attested to by the rarity of the organ pipe cactus itself, and the even more rare senita cactus, both of which are found nowhere else in the United States.
Prevalent plants include: buckhorn cholla, creosote bush, chain-fruit cholla, teddy bear cholla, ocotillo, bursage, Englemann's prickly pear, barrel cactus, jojoba, Mexican jumping bean, Christmas cactus, pencil cholla; and palo verde, oak, juniper, ironwood and mesquite trees.
Organ Pipe Cactus
There are six varieties of rattlesnakes, as well as Gila monsters and scorpions at Organ Pipe. These animals play an important role in the ecology of the desert and should not be harmed. They include the roadrunner, western diamondback rattlesnake, red-tailed hawk, coyote, cactus wren, javelina, desert tortoise, Gila monster, Gila woodpecker and white-winged dove.
As elsewhere in southern Arizona, steep linear mountain ranges are separated by sloping desert plains melting into pediments. All the mountains in Organ Pipe are fault-block ranges of different age and rock types.
The Bates Mountains in the northwestern portion of the park are flat-topped, sharp-edged mesas topped with Quarternary basalt lava flows.
The Ajo Range and the northwest slope of the Puerto Blanco Range are rugged, eroded Tertiary volcanic rocks with tilted layers of tuff, lava and breccia. The Ajos are cut through with numerous igneous dikes.
The southern Puerto Blanco Mountains and those in the Senita Basin are rounded hills of Mesozoic granite.
The central portion of the Puerto Blanco Mountains are light-colored metamorphic schist and gneiss from the Mesozoic period. In places they contain pegmatite dikes.
Organ Pipe Cactus NM Map - Map to help explore the park.
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