Estes Canyon-Bull Pasture Loop, Organ Pipe Cactus National Monument, Arizona

Distance: 4.1 miles (6.6 km)

Elevation: 2,400-3,400 feet (730 - 1035 m)

Difficulty: Moderately Strenuous

Time of Year: October - April

Looking for a great place to go for spring wildflowers? Organ Pipe Cactus National Monument might just be for you. Located on the Mexican border, this National Park Service site is one of the only places in the entire United States where the rare organ pipe cactus grows. Highly sensitive to freezing, the geographic range of this species almost completely mirrors the "frost line".

Reaching the top of Estes Canyon

Much of the park has been closed to the public in recent years due to Border Patrol issues. But, one area that remains open has probably the most spectacular trail in the park. This is the Estes Canyon-Bull Pasture Loop. With panoramic views of the lower Sonoran Desert, tons of wildflowers in spring, and lots of organ pipe cactus, this is a trail that can do no wrong.

Cactus in bloom

To access the trail, drive on the Ajo Mountain Drive off of Highway 85 opposite the park visitor center. The Ajo Mountain Drive is a well-graded dirt road that loops around some beautiful lowlands and up to the foothills of the Ajo range. The trail starts at the Estes Canyon Picnic Area.

The view from Ajo Mountain Road with organ pipe cactus scattered about

Follow the trail up through the Estes Canyon as it climbs following the dry wash. In spring, there should be lots of poppies, brittlebrush, and lupine in bloom. The first 1.5 miles is pretty easy until it climbs steeply up the south wall of the cliff. Here in the shade is a good place to take it easy and cool down if it is getting hot. Look for more frost-tolerant species here including jojoba and dodenea shrubs.

Look around in the understory
You might just glimpse a Gila Monster

As you emerge onto the plateau at the top of the canyon panoramic views of the entire national monument open up. At 2.3 miles you have reached Bull Pasture. This relatively flat basin contains some grasses that were used as pasture for old time ranchers.

If you are adventurous, you can scale to the summit of 4808 foot Ajo Mountain, the high point to the east of Bull Pasture, you can even make out the Sea of Cortez on a clear day.

The view from Bull Pasture

From Bull Pasture, you can take the Bull Pasture Trail, which will descend down the bajada back to Estes Canyon Picnic Area, to complete the loop. Make sure you bring plenty of water on this hike, since it can get surprisingly hot even in winter or spring in this neck of the woods. Organ Pipe Cactus National Monument is one of my favorite places in all of the Desert Southwest, especially from a botanical perspective. It is too bad so much illicit activity has resulted in much of it being closed. But, this place is still worth the visit!

Desert lupines in bloom