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By The Numbers: Organ Pipe Cactus National Monument


Organ pipe cactus. In the U.S., this rare plant grows only in Organ Pipe Cactus National Monument, typically on the south-facing slopes of rocky hills. NPS photo.

Arizona's Organ Pipe Cactus National Monument boasts diverse Sonoran Desert flora and fauna, interesting geology, traces of the historic Camino del Diablo trail, gorgeous scenery, and more. Here are some numbers that help to tell the park's story.


Acreage of the park. Federally protected wilderness accounts for a whopping 94 % share (312,600 acres).


Recreational visits in 2009. Visitation is skewed toward the cooler months, with nearly 80% tallied during October through April. The hot month of August averages less than 4% of annual visitation.


Earthquakes detected during a recent one-year period by a very sensitive seismic station placed in the park as part of the National Science Foundation’s 2,000-station EarthScope initiative.


Vascular plants identified in the park, including 28 cactus species. The extraordinary biological diversity of this desert park is reflected in 279 bird species, 53 mammals, 40 reptiles, four amphibians, and even one fish.

105° F (plus)

Typical daily maximum temperature during May through September. During October through April, afternoon temperatures are likely to be in the 60s or 70s.

32 miles

Length of the park border shared with Mexico. Illegal immigrants and drug smugglers pose significant hazards. The park's visitor center is named for Kris Eggle, an Organ Pipe Cactus ranger murdered by drug smugglers in 2002.

23 or so feet

Maximum height of the Organ Pipe Cactus (Stenocereus thurberi), the second-tallest cactus in the U.S. (after the saguaro). The plant, which may take 150 years to reach its maximum height, has 5 to 20 slender, spiny branches curving upward from a single short trunk near ground level.

21 miles

Length of the Ajo Mountain Drive, the park's most popular road for windshield touring and bicycling.

7.75 inches

Average annual precipitation. This amount, which can vary greatly from year to year, is far below that needed to sustain trees or grassland in such a hot environment. The result is a desert shrubland dominated by vegetation that can tolerate searing heat as well as frost, drought and flash flooding.


Natural arches in relatively accessible locations. Two can be viewed in Arch Canyon and another is accessible from Ajo Mountain Drive via a wayside trail. There are other arches in more remote locations.


Overnight stays in July 2009. That's one-hundredth of one percent of last year's 19,382 overnight stays.


Fish species found in the park. The tiny Quitobaquito pupfish (Cyprinodon macularius eremus) that inhabits the park's Quitobaquito springs, stream, and pond is a rare species found nowhere else in the U.S.


Amount of pack animal grazing permitted in the park. Pack animal users are required to carry supplemental feed such as pellets or rolled grains on all trips


Organ Pipe is indeed HOT. I didn't visit in August, but it was seriously cooking that day.

It was the first park I visited where the realities of our border security are plainly evident. Don't know if this is still true, but border patrol agents were actually set up outside the park, checking IDs as you go in and out. I don't know whether that turns off tourists or not, made me feel skittish about my own visit.

Hi from Ga. . .I was glad to see BP on the job when we were visiting Az. We were 'checked' several times in Southern Az. Securing the border is one of the most important issues in this region. Like I said, glad they were on the job.

Security is a concern at Organ Pipe Cactus National Monument. As CwB pointed out, there are several locations in southern Arizona where the Border Patrol stops traffic and seeks to find undocumented persons. Some Undocumented Aliens have passed through ORPI, and some have been arrested, just as every location along the U.S.-Mexican border. As someone who visited here recently, I was delighted to see so many law personnel including Pima County Sheriff's deputies, ORPI Law Enforcement and Border Patrol agents keeping the area safe for visitors. This is a beautiful place, one I wish more came to see in person. Don't let security issues keep you from visiting one of America's special places, Organ Pipe Cactus National Monument.

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