No doubt at all how Devils Postpile National Monument was named. It’s easy to imagine that the collection of dark rock columns could be a pile of posts pushed up from the depths of the earth by the old devil himself.

Got basalt? Long ago, Devil's Postpile was part of Yosemite National Park. (photo courtesy NPS)
Got basalt? Long ago, Devil’s Postpile was part of Yosemite National Park. (photo courtesy NPS)

Geologists have another explanation: An ancient lava flow helped create a formation of columnar basalt, as it’s known. Such columnar-joined basalt outcroppings occur elsewhere in the world—Ireland’s Giant Causeway and Scotland’s Fingal’s Cave in particular—but the postpile is one of the most perfect examples.

Tops of the postpiles were polished by glaciers.
Tops of the postpiles were polished by glaciers.

Subsequent glaciers excavated one side of the postpile, revealing a precipitous wall of columns 60 feet high. Glaciers also smoothed and polished the top of the postpiles, leaving behind a surface that resembles the tiled floor of some ancient Greek temple.

Devils Postpile measures some 900 feet long and 200 feet high, about the same size as the Acropolis of Athens. Most of the columns are hexagonal though these six-sided creations are joined by 3-, 4-, 5- and 7-sided postpiles.

Along with its famed rock, Devils Postpile National Monument’s other natural attraction for the hiker is the river–the Middle Fork of the San Joaquin. At one point the rushing river leaps 101 feet off the basalt cliffs, creating lovely Rainbow Falls. Stretches of the river are fly-fishing paradise with brook trout, brown trout and rainbow trout to be caught.

Because of the national monument’s small size, a walk to Devils Postpile, a stroll along the river and a visit to Rainbow Falls just about exhausts the hiking possibilities in the national monument. See The Trailmaster’s description of the Hike to Rainbow Falls.

However, this little island of national park land is a great jump-off place for more ambitious hikes into the nearby Inyo National Forest’s Ansel Adams Wilderness. Both the Pacific Crest Trail and John Muir Trail (traveling in tandem) cross the national monument. Fern Lake (13 miles round trip) and Minaret Lake (15 miles round trip) are two splendid all-day journeys that begin from Devils Postpile.

In the summer, visitors take the shuttle bus to Devil's Postpile.
In the summer, visitors take the shuttle bus to Devil’s Postpile.

Getting to the national monument is easy enough but requires some advance planning. More than 30 years ago the U.S. Forest Service restricted private vehicle access on the narrow entry road leading to Devils Postpile and instituted a shuttle bus service. The idea was to reduce the impact on the area and its steep, narrow roadway during the busy summer months. For a modest fee ($7 adults, $4 children 15 and under), the Eastern Sierra Transit Authority provides bus service from the Mammoth Mountain Main Lodge to to Devils Postpile National Monument and Reds Meadow Resort.

For more information: Devils Postpile National Monument, 
P.O. Box 3999
, Mammoth Lakes, CA 93546 Call (760) 934-2289.

To visit the national monument, you must use the Reds Meadow/Devils Postpile Shuttle. Certain exceptions apply (for example, early or late in the hiking season), but for the most part you should plan your hike with the shuttle schedule in mind.