Devils Postpile National Monument: Rare Basalt Formations and Volcanic Columns. Photo Credit; Frank Kovalchek, Devils Postpile National Monument near Mammoth Lakes.jpg
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Published February 25, 2026
Devils Postpile National Monument: Rare Basalt Formations and Volcanic Columns
Near Mammoth Lakes in the eastern Sierra, Devils Postpile National Monument protects one of the world's finest examples of columnar basalt joints; a dramatic 60-foot-high formation created by ancient lava cooling. This compact monument offers short trails amid redwood-like basalt columns and surrounding forest.
A Volcanic Basalt and Forest Crossroads
The monument blends towering hexagonal basalt columns (formed ~100,000 years ago), mixed conifer forest, and the Middle Fork San Joaquin River. Wildlife includes black bears, deer, birds, and seasonal wildflowers; the columns create unique microhabitats for lichens and insects.
Adventure With a Conservation Conscience
Short trail (0.4-mile round-trip) to Postpile base; continue to Rainbow Falls (2.5 miles round-trip). Ranger talks seasonal.
Access is intentional: mandatory shuttle (summer only, fee), pack out waste, stay on paths. Monument open late May to mid-October; winter access limited.
Devils Postpile National Monument delivers rare basalt formations hiking in volcanic wonder. For those seeking hexagonal columns and forest immersion, the short trail repays close-up awe; a geological masterpiece.