US Park Info: Devil's Postpile National Monument
Geologic Wonders along a River of Life High on the western slope of the Sierra Crest, nature reveals two of its wonders - the weirdly wonderful "postpile" and the lovely San Joaquin River with its dramatic Rainbow Falls.
The geologic formation that is "the Postpile" is the world's finest example of unusual columnar basalt. Its columns of lava, with their four to seven sides, display a honeycomb pattern of order and harmony.
Another jewel in the Monument is the San Joaquin River. Along the river corridor, the Monument flourishes with life. Meadows burst forth with flowers that nourish deer, birds, and butterflies. This portion of the San Joaquin is a designated Wild Trout River where both novice and expert can play the waters for four species of trout. Lining the river are a combination of old-growth red-fir forest and new growth rejuvenated by fire. On the lower reaches of the Monument's 2.5 miles of river course, rainbows frequently sparkle over their namesake -- the 101-foot drop of Rainbow Falls.
In addition to its geologic wonders and the beauty and diversity of the San Joaquin River, the monument is a portal to the great Sierra backcountry. Some 75% of the monument is part of the Ansel Adams Wilderness. It is traversed by the historic John Muir and Pacific Crest trails; you can follow a trail from here to Mexico or Canada!
At 800 acres, Devils Postpile National Monument may be considered small by some, yet its natural and recreational values abound.
Formation of the Postpiloe
The "postpile" is a fascinating geologic formation. The process of its creation began almost 100,000 years ago, when molten basalt lava flowed from the earth one mile upstream from the modern-day monument. Imagine a mass of lava 400 feet deep flowing like a river for three miles. As the lava slowly cooled from the outside toward the middle of the flow, ideal conditions caused the lava to crack into long post-like columns. (Look at the surface of the mud in a dried-out puddle and you may see similar polygonal shapes.) During the last major ice age, which ended about 10,000 years ago, a glacier sculpted away the top layers of lava. It revealed the internal fractured lava mass and exposed a wall of columns 40 to 60 feet high. Some say it resembles a giant pipe organ. Our 140,000 visitors per year each find their own metaphor to describe it, but all of them call it "fascinating!"
Operating Hours for Devil's Postpile National Monument
Summer season only: Opens in late June to early July, weather permitting.
Closure in the fall depends on weather. Ranger Station open July - August 7 am - 6 pm (closes for emergencies).
Winter months - Closed.
How to Get to Devil's Postpile National Monument
What's the Nearest Airport to Devil's Postpile - Closest commercial airport is Reno, Nevada.
How to Drive to Devil's Postpile National Monument - Drive 10 miles west from U.S. 395 on S.R. 203 to Minaret Summit & then 7 miles on a paved, narrow mountain road. Most visitors must park at Mammoth Mountain & use the shuttle
Weather & Climate
At an altitude of nearly 7500 feet, the monument experiences cold, snowy winters, which closes the park. The summers are usually cool, with afternoon thundstorms.
The visitor center should be accessible.
There are 6 campgrounds in the area totaling over 180 sites. All are first-come, first-served; all close during winter. The campground in the monument, administered by the National Park Service, has 21 sites. The U.S. Forest Service administers the other 5 campgrounds: Agnew Meadows, Soda Springs, Pumice Flat, Minaret Falls, & Reds Meadow. Group campsites can be reserved at Agnew Meadows & Pumice Flat: 1-877-444-6777 or www.reserveusa.com.
Shuttle Fare (buy tickets at Mammoth Mountain Inn):
-Under age 5 - FREE
-Ages 5-12 - round trip $5.50; one-way $3
-Ages 13-18 - round trip $7.50; one way $4
-Age 19 & over - round trip $9.50; one way $5
-Stop to stop within the valley (from Agnew Meadows to Reds Meadow Resort: free
-Hikers must purchase a $5 one-way ticket to exit the Valley
-Exceptions to shuttle use: walkers, bicyclists, vehicles carrying 11 or more passengers, vehicles carrying non-ambulatory passengers, people with valid camping permits, overnight guests at Reds Meadow resort or packstation, & vehicles pulling horse trailers or boats.
-Backpackers: wilderness permits do not include permission to drive to the trailheads or to the valley; you must use the shuttle or walk. Shuttles have racks which accommodate backpacks
*This shuttle system is necessary to lessen impacts on the environment & the visitor. Please relax & enjoy the view on your ride.*