Explore Devils Postpile National Monument

Devils Postpile National Monument is a unique geological formation located in the eastern Sierra Nevada mountains near Mammoth Mountain California. The monument features a series of towering basalt columns that were formed over 100,000 years ago by the cooling and solidification of lava flows. These columns are perfectly shaped and stacked in a unique hexagonal pattern, creating a breathtaking natural wonder that is unlike anything else in the world.

Visitors to Devils Postpile National Monument can hike to the top of the columns and marvel at the towering basalt formations. The park offers a range of hiking trails that lead visitors through stunning forests, past tranquil lakes, and up to the top of the columns themselves. The most popular trail is the 2.5-mile round-trip hike to the top of the columns, which provides visitors with a spectacular view of the surrounding landscape. Visitors can Access the JMT also near the Monument as well as visit the Rainbow Falls viewing area while inside the park.

In addition to its hiking trails, Devils Postpile National Monument also offers a number of other outdoor activities, including fishing, camping, and wildlife viewing. The park is home to a diverse array of flora and fauna, including black bears, mountain lions, and a variety of bird species.

One of our favorite things todo when visiting devils Postpile to to get off the bus Early and walk the entire valley enjoying the sights and sounds of this wilderness region. There are multiple bus stops on the route. We enjoy visits to Starkweather Lake and walking along the Middle Fork San Joaquin River.

Devils Postpile National Monument is not only a beautiful natural wonder but also an important site for geological research. The monument provides scientists with a unique window into the Earth’s past, allowing them to study the processes that formed these incredible basalt columns.

Overall, Devils Postpile National Monument is a must-visit destination for anyone interested in geology or nature. With its towering basalt columns, beautiful hiking trails, and abundant wildlife, the park offers visitors a chance to experience the natural beauty of California’s eastern Sierra Nevada mountains.

How did Devils Postpile come to Be

The creation of the Devils Postpile began around 100,000 years ago, during the Pleistocene era, when a massive lava flow covered the area. As the lava cooled and solidified, it began to contract and crack, forming deep vertical columns that radiate outward from the center of the flow. Or so we think. Current studies suggest that the Postpile was formed less than 100,000 years ago when a cooling lava flow cracked into multi-sided columns. However, to fully understand the geologic setting of the Postpile we must go back millions of years to a time when there was no Sierra Nevada and California was a shallow sea.

Over time, these columns were exposed to the elements, as erosion and glacial activity slowly wore away the surrounding rock and soil. As the columns were gradually exposed, they began to take on their distinctive hexagonal shape, caused by the natural fracturing and cooling of the basalt.

The Devils Postpile columns are notable for their uniformity and precision, with many of the columns measuring over 60 feet in height and 2 feet in diameter. The columns are arranged in a series of massive hexagonal columns, each separated from its neighbor by a narrow vertical joint.

The creation of the Devils Postpile was a remarkable natural process that took place over many thousands of years. Today, visitors to the monument can marvel at the sheer size and complexity of the columns, and learn about the geological forces that created this striking natural wonder.

How do Basalt hexagon columns form

Basalt hexagonal columns are a fascinating geological formation that occur when lava cools and solidifies. The process begins with a volcanic eruption, during which molten lava flows out of the earth and spreads across the surrounding landscape.

As the lava cools, it begins to contract and solidify from the outside in, forming a solid outer layer that gradually thickens over time. As the lava continues to cool, it begins to contract and crack, creating deep vertical fractures that extend down into the rock.

As the lava continues to cool and contract, these fractures gradually widen and deepen, creating long, straight columns that radiate outward from the center of the lava flow. These columns are typically hexagonal in shape, with six flat sides and sharp edges that fit together like puzzle pieces.

The hexagonal shape of the columns is caused by the natural fracturing and cooling of the basalt, which creates a series of flat, angular faces that fit together perfectly. The columns can vary in size, with some reaching heights of up to 40 feet or more.

Over time, weathering and erosion can cause the columns to break apart and topple over, creating the dramatic and awe-inspiring landscapes that we see today. Basalt hexagonal columns can be found all over the world, from Ireland’s Giant’s Causeway to the Devils Postpile in California, and they are a testament to the incredible power and beauty of the natural world.

Is there Camping available at Devils Postpile

Not at this time. The National Park Service is looking at different ways to increase recreational river access for fishing, easy walking and scenic picnicking along the river. As part of this effort, Devils Postpile National Monument is considering the future of the park’s 20-site campground.

The 20-site campground has been closed since 2016 to address infrastructure repairs, safety needs, and the impacts of intense winters. As a result, staff has had an opportunity to reconsider additional opportunities for the campground. The monument has limited and congested day-use facilities that do not meet the demands of the 135,000 annual visitors, while camping is readily available nearby in U.S. Forest Service campgrounds. Day users average 1,500 per day rising to 2,500 on weekends and holidays. The campground on the busiest day would have less than 100 people.

Other Campgrounds in the Area

Outside of the monument, there are five Forest Service campgrounds located within Reds Meadow Valley. From north to south, these are: Upper Soda SpringsPumice FlatPumice Flat GroupMinaret Falls, and Reds Meadow campgrounds. Sites in these campgrounds are $28 per site per night.

All of these campgrounds are first-come, first-served with the exception of the Pumice Flat Group, which is reservable via www.recreation.gov.

What are the five best day hike options at Devils Postpile

There are many great hiking trails at Devils Postpile National Monument, ranging from easy walks to challenging backcountry treks. Here are five popular hikes that visitors can do during a day visit: On your trail visit in the summer visitors often see PCT through hikers on the trail as well as at the Reds Meadow Store.

  1. Devils Postpile Loop Trail: This easy 0.8-mile loop trail takes visitors past the iconic basalt columns of Devils Postpile, as well as the roaring waters of the San Joaquin River. Cross over the middle fork of the San Joaquin river on the PCT / John Muir Trail bridge near the Basalt columns
  2. Rainbow Falls Trail: This moderate 5.4-mile round-trip hike takes visitors through a beautiful forested area to the stunning Rainbow Falls, a 101-foot waterfall that cascades into a deep pool below. This is a popular spot on a hot summer day as the cool waters of the San Joaquin waters pour over the edge into a beautiful pool
  3. Minaret Falls Trail: This moderate 3.6-mile round-trip hike takes visitors through a picturesque meadow and past several cascading waterfalls to the base of Minaret Falls, a beautiful 80-foot waterfall.
  4. Ansel Adams Wilderness Loop Trail: This challenging 20- plus mile loop trail is best done as backpacking loop but takes visitors through the rugged wilderness of the Ansel Adams Wilderness, offering stunning views of towering peaks, alpine lakes, and pristine meadows. Hikers enjoy the views from Thousand Island lakes, Garnet Lake and Shadow lake.
  5. John Muir Trail: This famous trail runs through Devils Postpile National Monument and offers visitors the opportunity to hike a small section of this legendary trail. The section of the trail that runs through the monument is about 2 miles long and provides beautiful views of the surrounding mountains and valleys.

Shuttle Bus Information

Between mid-June and mid-September a mandatory shuttle bus brings visitors to the monument and the rest of the Reds Meadow Valley including the Rainbow Falls Trailhead.

Devils Postpile does not charge an entrance fee, but there are still fees associated with a visit to the monument. Visit the shuttle bus page for information on fees for the mandatory shuttle bus (mid-June through mid-September) and for visits outside of the mandatory shuttle bus season.

Entrance Fees:

Reds Meadow Shuttle Bus Day Pass – Adult – $15.00

The Reds Meadow Shuttle Bus, operated by Eastern Sierra Transit, has provided transit service into the Reds Meadow Valley and to the Devils Postpile National Monument for over 30 years. Most visitors must ride the shuttle to access the Valley and Devils Postpile.

Reds Meadow Shuttle Bus Day Pass – Child (3-15) – $7.00

The Reds Meadow Shuttle Bus, operated by Eastern Sierra Transit, has provided transit service into the Reds Meadow Valley and to the Devils Postpile National Monument for over 30 years. Most visitors must ride the shuttle to access the Valley and Devils Postpile.

John muir trail

Hiking to Devils Postpile National Monument When Reds Meadow Road is Closed

Reds Meadow Road, which provides vehicle access to Devils Postpile National Monument, is typically closed from sometime in October to sometime in June. During this time, the only way to reach the monument is on foot. Keep in mind that the area may be snowy, making travel and navigation extremely difficult. We don’t recommend traveling to the monument in snowy conditions unless you’re a skilled wilderness traveler competent with cross-country navigation using a map and compass (even if you have GPS). Both these hikes or skis are strenuous.

You can hike or ski from the Mammoth Mountain Main Lodge to the monument on the Reds Meadow Road. The trip is about 17 miles round trip with nearly 2,000 feet of total elevation gain. (If the road is open to Minaret Vista, the trip is 15 miles round trip.)

It is also possible to hike over Mammoth Pass from Horsehoe Lake in the Lakes Basin, which is about 11 miles round trip with over 2,000 feet of total elevation gain. The road to the Lakes Basin is typically closed from sometime in October until sometime in May, so this isn’t usually an option except for a few weeks before Reds Meadow Road opens.

Backpacking from Devils Postpile National Monument When Reds Meadow Road is Closed

Reds Meadow Road, which provides vehicle access to Devils Postpile National Monument, is typically closed from sometime in October to sometime in June. This affects access to Beck Lake, Fern Lake, John Muir Trail North of Devils Postpile, and Minaret Lake trailheads in Devils Postpile as well as several other Inyo National Forest trailheads elsewhere in Reds Meadow Valley.

When the Reds Meadow Road is closed at the Main Lodge, you can park in the parking areas alongside the road (lots A, B, C, etc.), but not in the Mammoth Mountain Inn parking lot.

When the road is open to Minaret Vista, you can park at any of the parking areas there. Do not block the road or park on vegetation.

Food lockers are not available at the Main Lodge or Minaret Vista; do not leave food, drinks, toiletries, trash, or other scented items in your car.

Your wilderness permit for a Reds Meadow Valley trailhead is valid if you’re starting your hike at the Main Lodge or Minaret Vista and hiking to the trailhead indicated on your permit. If you want to instead start in the Lakes Basin, you will need a permit for Horseshoe Lake

Middle Fork San Joaquin River
Middle Fork San Joaquin River


The San Joaquin River is a designated Wild Trout River with ample fishing opportunities for all abilities. With a valid California fishing license, anglers can keep up to five fish. Venturing further from the parking lot, away from Soda Springs Meadow, will give you a bit more solitude, but there is plenty of fishing near the parking lot. If you do head out along the river bank to fish, please use established trails and limit your impact. Please help preserve the river for wildlife and other anglers by packing out all trash and fishing line.

Other fishing opportunities are available at nearby Sotcher and Starkweather Lakes. For more information on regulations and limits, please visit the California Department of Fish and Game site.

Cycling and Mountain Biking

Road Biking

Cycling the road into the Reds Meadow Valley is a scenic adventure. If you are interested in biking into Reds Meadow, please consider the following advisories:

  • To avoid head-on collisions, do not pass stopped or slowed traffic as they may be waiting for an oncoming vehicle to pass safely.
  • On the downhill stretch into Reds Meadow, the road speed limit is 15 mph. By law, this speed limit applies to both cyclists and vehicles.
  • Downhill traffic must yield to uphill traffic and must stay to the right.
  • The road is narrow, winding, and steep. Be sure your brakes are in good condition before beginning your descent.
  • Riding into the valley during peak visitation times (11:00 a.m. to 4:00 p.m.) is not recommended.
  • Bikes will be loaded and unloaded only at the Adventure Center and at Reds Meadow Resort if space is available.
  • Shuttle buses can only transport a total of two bicycles at a time.
  • There is a speed bump on the road into Devils Postpile National Monument.
  • Helmets are recommended for all riders and are required for riders under 18 years of age.
  • All cyclists ride at their own risk. Please look after both your safety and the safety of others on the road.

If cyclists ride the shuttle buses out of the valley, they must pay the transportation fee. Those who cycle in and out of the valley (and don’t use a shuttle bus) are exempt from the fee.

Mountain Biking

Mountain biking is generally not permitted in the Reds Meadow Valley and is not permitted anywhere in Devils Postpile National Monument. The one exception is the Starkweather Trail, which starts either at Starkweather Lake or at Minaret Vista. Mountain biking is only allowed on this trail AFTER the shuttle buses have stopped running for the season, which is generally the Wednesday after Labor Day (which is the first Monday in September). This is also a popular hiking trail, so ride cautiously. The nearby town of Mammoth Lakes and the surrounding Inyo National Forest offer endless mountain biking possibilities.

Snowshoeing and Skiing

The Reds Meadow Valley, although closed to vehicles in the winter, is available to backcountry skiers and snowshoers. The very strenuous trip to Devils Postpile is nine miles each way, with nearly 2,000 feet of elevation change. This is a true winter wilderness experience and travel into the valley can be hazardous. For those with proper avalanche safety skills and physical conditioning, however, the valley offers outstanding touring and provides a gateway to the High Sierra backcountry. There are no facilities available in the valley in the winter and all travelers should be prepared to be self sufficient.

Mammoth Pass Trail

While evidence of the original trail over the Mammoth Pass may be difficult to locate, modern day trails follow the general corridor used by American Indian traders both before and after Euro-American settlement. The trail connects the North Fork San Joaquin Valley to the Mammoth Lakes Basin by way of Devils Postpile.At 9,300 feet, Mammoth Pass is the lowest point for more than 250 miles along the Sierra crest, and has been important to the history of this area. In the 1860s, sheepherders came over Mammoth Pass from the east to graze their flocks on the alpine and subalpine meadows in and around the Middle Fork Valley. The trail was also used by miners, U.S. cavalry patrols during the early history of Yosemite National Park, and American Indians. Use has continued today by Forest Service trail crews, hikers, and pack-stock outfits.In the first decade after the monument was established in 1911, most visitors arrived by crossing the Sierra crest from the east by way of Mammoth Pass on the south shoulder of Mammoth Mountain. Between the 1950s and 1970s, the area became the focus of a citizen movement led by local conservationists, packers, and tourism business owners to prevent the construction of a trans-Sierra highway, which would have followed the general route of the historical trail. Due to the history associated with this trail, the Mammoth Pass Trail, extending from the North Fork San Joaquin Valley through Devils Postpile to the Mammoth Lakes basin, may therefore qualify for inclusion on the National Register of Historic Places as a cultural landscape.

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