Hot basalt lava flowing down into the Red Meadow Valley, met by receding ice age glaciers, worked together to form Devils Postpile roughly 100,000 years ago.
The Devils Postpile National Monument, largely contained in the Ansel Adams Wilderness, is a gateway to the High Sierras backcountry range.
The formation is a rare sight in the geologic world and ranks as one of the world's finest examples of columnar basalt. Its columns tower 60 feet high and display an unusual symmetry. Another wonder is in store just downstream from the Postpile at Rainbow Falls, once called a gem unique and worthy of its name. When the sun is overhead, a bright rainbow highlights the spectacular falls.
At 800 acres, Devils Postpile National Monument may be considered small by some, yet its natural and recreational values abound.