Devils Postpile National Monument protects one of the world's finest examples of columnar basalt, where towering hexagonal columns rise up to 60 feet like a massive stone pipe organ. The monument's formation began around 100,000 years ago when lava flows cooled and cracked into these perfectly geometric columns, later polished smooth by glacial action. Families can explore both the postpile formation itself and the spectacular 101-foot Rainbow Falls, where the San Joaquin River creates stunning rainbows in the mist. At 7,560 feet elevation in the Sierra Nevada, this compact monument offers an incredible geology lesson alongside pristine mountain wilderness.
Junior Ranger Program at Devils Postpile National Monument
The Junior Ranger program at Devils Postpile engages kids with hands-on geology activities and volcano experiments that bring the monument's fascinating formation story to life. Young rangers complete an activity booklet while exploring the iconic postpile formation and learning about the area's unique ecosystem and wildlife.
- Touch and examine real volcanic rock samples up close
- Learn how massive ice age glaciers carved the landscape
- Spot rainbow colors in the mist at Rainbow Falls on sunny days
Program Details
Download Junior Ranger Booklet
Get a head start! Download and print the booklet before your visit.
Source: NPS Junior Ranger Program Page
Best Ages for Devils Postpile National Monument
Ages 4–6
Young kids love the scavenger hunt activities and drawing exercises that help them observe the unique rock formations up close. The sensory activities, like feeling the smooth basalt columns and smelling the Jeffrey pine bark, truly engage their curiosity. Parents should plan to help with reading and writing portions of the booklet.
Ages 7–10
This age group excels at the geology activities, including identifying hexagon shapes in the columns and understanding the volcanic formation process through the booklet's step-by-step illustrations. The Leave No Trace activities and National Park Service symbol matching exercises help them grasp conservation concepts. Most kids this age can complete the required number of activities matching their age with minimal adult help.
Ages 10+
Older kids and teens must complete 10 activities, including all challenging level exercises that dive deep into succession after forest fires, geological processes, and watershed science. The booklet's complex word search about the San Joaquin River and the succession maze following the Rainbow Fire provide engaging challenges. Many families find the interview-a-ranger option particularly appealing for this age group.
Planning Your Visit
Getting There
During peak season (mid-June through Labor Day), you must park at Mammoth Mountain Adventure Center and take the mandatory shuttle to Devils Postpile, as private vehicles aren't allowed on the access road. The shuttle runs regularly but can have wait times during busy periods. Outside peak season, you can drive directly to the monument via the steep, narrow mountain road from Mammoth Lakes.
Van & RV Notes
RVs and large vehicles cannot access Devils Postpile directly due to the narrow, winding mountain road with tight switchbacks. Van families should plan to park at Mammoth Mountain Adventure Center and use the shuttle system during operating season. The nearest RV camping with hookups is at Mammoth Lakes RV Park in town, though dispersed camping is available in surrounding Inyo National Forest areas.
Best Time to Visit
Visit between mid-June and early October when the access road is clear of snow and the shuttle system operates. July and August offer the warmest weather but also the biggest crowds and afternoon thunderstorms. Early season (June) and fall (September-October) provide cooler temperatures and fewer visitors, though nights can drop into the 30s by October.
How Long to Spend
Plan a full day to complete the Junior Ranger program and hike to both the postpile formation and Rainbow Falls. Most families spend 2-3 hours on Junior Ranger activities and another 2-3 hours hiking the easy trails to see both main attractions.
Don't Miss
Walk to the top of the postpile formation to see the glacially polished hexagonal column tops - kids are amazed by the geometric perfection visible from above. The hike to Rainbow Falls is absolutely worth it for the spectacular waterfall and potential rainbow sightings in the morning mist, plus you'll see evidence of the 1992 Rainbow Fire recovery along the trail.
Fun Facts for Kids
The Devils Postpile columns are hexagonal because that's the most efficient way for cooling lava to crack - just like how soap bubbles naturally form hexagons when packed together
A glacier polished the tops of the postpile columns around 20,000 years ago, creating the smooth surface you can walk on today
Rainbow Falls got its name because rainbows appear in the mist almost every morning when the sun hits the waterfall at the right angle
The Jeffrey pine trees at Devils Postpile have bark that smells like vanilla or butterscotch when you sniff between the cracks
Plan Your Stay
Save on park entry with the America the Beautiful Pass — $80 for unlimited access to all 400+ National Park sites for a full year.
Where to Stay
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Nearby Parks to Earn More Badges
Sequoia & Kings Canyon National Parks
Yosemite National Park lies just 45 minutes away and offers iconic granite cliffs like El Capitan and Half Dome that contrast beautifully with Devils Postpile's volcanic columns
Yosemite National Park
Yosemite's Tuolumne Meadows section provides high-altitude alpine scenery and is accessible via Tioga Pass during summer months for families wanting to explore the Sierra Nevada's gentler side
Yosemite National Park (Tuolumne Meadows)
Sequoia & Kings Canyon National Parks showcase the world's largest trees about 2.5 hours south, making an excellent complement to Devils Postpile's geological wonders
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