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Neighboring Parks

Devils Postpile National Monument

See hexagonal shaped columns of rock protruding from a fallen pile, but time your season and daily hours.

During the summer months, hunt down this stack of lava columns called Devils Postpile by descending a remote narrow road deep into Reds Meadow and then hiking a trail to the rock pile. The national monument housing this glacial wonder, just outside the eastern boundary of Yosemite near Mammoth Lakes, opens its roads from mid-June to mid-October, but if you’re up for a strenuous snowshoe or ski adventure, you can explore the monument year-round.

Devils Postpile National Monument and the Inyo National Forest share roads, shuttles and trails so directions can be confusing. Consult a map ( to get an overview of the public lands.

You not only need to arrive in the right season, but you need to be cognizant of the time of day. The access road to Devils Postpile is so narrow and parking so limited that the national monument won’t let you drive down the road during daytime hours, 7 a.m. to 7 p.m. Take a mandatory shuttle ( during these hours unless you meet their requirements for road privileges. Exemptions include in-park lodging or camping, hauling of recreational equipment or horses, and handicap tags.

The park is open 24-hours during the season, so before or after the shuttle hours, the road is open to anyone who wants to venture out on it. Just know that you may need to back up to a wider section of road if you meet another vehicle. If you’re lucky, the only thing that will approach your vehicle is a black bear scurrying across the road into the woods.

Broken hexagonal columns at the foot of Devils Postpile
Broken hexagonal columns at the foot of Devils Postpile (Photo: Gloria Wadzinski)

At the end of the road, you’ll find a small parking lot outside the trailhead. The hike is short – less than a mile and fairly level so the walking is easy. Devils Postpile comes into view suddenly, a very strange sight indeed. There are tall, 60-foot stone pillars ascending out of a pile of broken rock. Look closely and you’ll notice the oddly hexagonal shape of the columns. A nearby interpretive sign explains:

“Molten lava and glacial ice shaped these unusual rock columns. Basaltic lava more than 400 feet deep filled this narrow valley nearly 100,000 years ago. As the lava cooled, cracks formed on the surface to release built-up tension. These cracks formed into hexagons, one of nature’s most efficient and stable shapes. The cracks deepened as the interior cooled to form basaltic columns. During the last ice age, about 20,000 years ago, a glacier exposed this cliff of columns and polished the top surface. The postpile continues to be sculpted by weathering and earthquakes that break and change the formation.”

Rainbow Falls in Devils Postpile National Monument
Rainbow Falls in Devils Postpile National Monument (Photo: Getty Images)

Continue on the trail to Rainbow Falls, 1.25 miles one-way, to see the 101-foot waterfall plunge down to the Middle Fork of the San Joaquin River. Again, timing is important. Approach the waterfall at the right time on a sunny day and you will see multiple rainbows dancing above the mist. Make your way back to the ranger station or you can make this a loop hike using the shuttle to transport you from stop #9, the Rainbow Falls Trailhead to stop #6, the ranger station.

For more information, visit

To get to Devils Postpile National Monument from Yosemite’s East Entrance, head south on Highway 395 and then make a right (west) onto Mammoth Scenic Loop. The trip takes about an hour to get to the entrance to the monument.

See other nearby attractions in Mono County and Inyo County