Organ Pipe Cactus National Monument

If necessity is indeed the mother of invention, then adversity must be the mother of adaptation, for the cruel heat of the Sonoran Desert has given rise to adaptation in the extreme. Visitors to Arizona's Organ Pipe Cactus National Monument can see proof of nature's resourcefulness everywhere, from the kangaroo rat, which drinks no water yet thrives in one of the world's most arid climates, to the creosote bush, which manufactures its own natural herbicide to prevent competition for water by encroaching plant life.

Organ Pipe Cactus National Monument.
Look for the rare Organ Pipe Cactus on the south-facing hill slopes in the
Organ Pipe Cactus National Monument.

The most visible adaptations to this extreme climate are the stunning and sometimes bizarre forms of the monument's 26 species of cactus, including cholla, prickly pear, senita, saguaro, and the towering organ pipe cactus, with its huge vertical arms stretching up to 25 feet high. Although plentiful in Mexico, the organ pipe is rare in the United States, its northern range limited almost exclusively to the monument. Evidence can also be found of those who failed to adapt. Unmarked graves along old El Camino del Diablo, "The Devil's Highway", are somber testament to the unforgiving nature of this desert. Portions of this historic trail are paralleled by the 53-mile Puerto Blanco Drive, one of two scenic loops available to motorists.

The Puerto Blanco traverses a stunning array of scenery, from the oasis of Quitobaquito to the heart of the Sonoran Desert, featuring organ pipe cacti, saguaros, and elephant trees. The shorter Ajo Mountain Drive also features impressive desert landscapes and large stands of organ pipe cactus. Besides these two scenic drives, the national monument also contains a few unimproved dirt roads leading to abandoned mines, empty ranch houses, and other historic sites. For those wanting a closer look, there are several excellent hiking trails, some with interpretive signs or pamphlets explaining important natural features.

The trails offer breathtaking views of nearby mountains and the surrounding terrain. The best months to hike are October through April. The passage from day to night in the Sonoran Desert is a transition from one world to another. Jackrabbits, snakes, kangaroo rats, and elf owls emerge from their underground burrows, cactus holes, and other cool and sheltered spots where they have spent the day. Even the organ pipe cactus waits until the sun has set to open its delicate lavender-white flowers, closing them again near sunrise.

Of those animals that prefer daylight, such as lizards, bighorn sheep, and most birds, the majority limit activity to early morning or late afternoon during the summer, seeking shade during the hottest part of the day, when air temperatures can reach 118 degrees and ground temperatures can escalate to a blistering 175 degrees.

Organ Pipe Cactus National Monument Information

Address: Located along the US/Mexican Border, south of Ajo, west of Tucson, and east of Yuma
Telephone: 520/387-6849
Hours of Operation:

  • The park is open 24 hours a day
  • The visitor center is open daily 8 a.m. - 5 p.m.

Admission: $8 per vehicle

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To learn more about national monuments, memorials, and historic sites, and other travel destinations in North America, visit:


Eric Peterson is a Denver-based author who has contributed to numerous guidebooks about the Western United States.