A wall of hexagonal basalt columns and a rainbow waterfall in the High Sierra.
Photo: Frank Kovalchek from Anchorage, Alaska, USA · CC BY 2.0 · via Wikimedia Commons
Tucked into the High Sierra near Mammoth Lakes, Devils Postpile protects one of the world's finest displays of columnar basalt — a sheer wall of tall, near-perfect hexagonal columns formed when a lava flow cooled and contracted roughly 100,000 years ago. Just downriver, the 101-foot Rainbow Falls throws a rainbow across its mist on a sunny afternoon. It's a small, magical place at about 7,600 feet — and snowbound most of the year, open only about June through October.
The columns are a short, flat walk from the ranger station, and a quick climb to the Top of the Columns reveals their polished, tile-like tops, scraped flat by Ice Age glaciers. The John Muir and Pacific Crest Trails run right through, and Reds Meadow valley makes a fine basecamp once you're in.
The catch is access: in peak summer you can't drive in during the day — you ride the mandatory Reds Meadow shuttle from Mammoth Mountain (a fee applies), and both the shuttle dates and the season shift every year with the snow, so check before you go. It's high country, so days are mild and nights cold, with afternoon thunderstorms common; pair it with Mammoth Lakes and the eastern Sierra.
A sheer wall of tall, strikingly symmetrical hexagonal basalt columns — up to 60 feet — from a ~100,000-year-old lava flow, among the finest columnar basalt on Earth.
Insider tipAn easy ~0.4-mile walk from the ranger station — flat and quick once you're off the shuttle.
Plan a trip to this spot →A short, steeper spur climbs to the top of the formation, where you look down on the polished, tile-like column tops — burnished flat by Ice Age glaciers.
Insider tipDon't skip the climb — the honeycomb view from above is the 'wow' most day-trippers miss. Watch your footing near the edge.
Plan a trip to this spot →A 101-foot waterfall on the Middle Fork San Joaquin, about 2.5 miles from the ranger station, where the mist throws a rainbow across the gorge.
Insider tipGo midday, when the sun is high enough to light the spray and produce the rainbow.
Plan a trip to this spot →Naturally carbonated cold spring water bubbles up near the clear Middle Fork San Joaquin River.
Insider tipA quirky, kid-pleasing short detour off the main trails — don't drink untreated water; it's about the novelty.
Plan a trip to this spot →The famed JMT and PCT run right through the monument — one of the most celebrated stretches of both long trails.
Insider tipDay visitors can walk a piece of the JMT/PCT; Reds Meadow is also a classic thru-hiker resupply stop — fun people-watching.
Plan a trip to this spot →The broad volcanic valley holding the monument, trailheads, a small store, and the resort — your basecamp once the shuttle drops you.
Insider tipRiding between stops within the valley is free once you've paid to get in — plan your stops.
Plan a trip to this spot →High Sierra (~7,600 ft): short, cool, dry summers and long, deeply snowy winters. Even in July–August, highs reach only the upper 70s and nights drop to the mid-40s; afternoon thunderstorms are common, so go early. The monument and Reds Meadow Road are open only about June–October, entirely snow-dependent — late snow delays opening and early storms can close it.
Via Mammoth Lakes — but a mandatory shuttle replaces driving in summer.
From Mammoth Lakes, the staging point is the Mammoth Mountain Adventure Center. In peak summer a mandatory shuttle runs (you can't drive in then; a fee applies, ~$15 adult). The road/monument open only ~June–October, snow-dependent — verify dates.
A small valley campground and resort cabins; hotels in Mammoth Lakes.
A small campground at Devils Postpile and Forest Service sites nearby, plus Reds Meadow Resort cabins and a café — primitive, high, seasonal.
Booking tipCampers with reservations and resort guests can drive the road.
The full-service base (~30–45 min up the hill) — hotels, condos, and dining — ride the shuttle down each day.
Booking tipThe practical choice for most road-trippers.
Do I have to take a shuttle?
In peak summer, yes — during the day you can't drive your own car in; you park at the Mammoth Mountain Main Lodge and ride the Reds Meadow shuttle (about $15 adult, $7 child). You can drive in (paying a small USFS fee) only before 7 a.m. or after 7 p.m., or if you qualify (campers, resort guests, disability placard). Verify current dates.
When is it open?
Only about June through October, and it's entirely snow-dependent — the high road must be plowed open in early summer and can close with the first fall storms. Always confirm current status with NPS.
How long are the hikes?
The columns are an easy ~0.4-mile walk from the ranger station (with a short climb to the Top of the Columns); Rainbow Falls is about 2–2.5 miles each way (~5 miles round trip).
Should I worry about altitude?
Possibly — the monument sits around 7,600 feet and you stage even higher at Mammoth. Hydrate, pace yourself, and consider acclimating a day in Mammoth Lakes first.
When's the best time to go?
Mid-July through September for the most reliable access and mild days. Go early to beat crowds and afternoon storms, and visit Rainbow Falls around midday for the rainbow.
Can I combine it with Mammoth or Yosemite?
Yes — it pairs naturally with Mammoth Lakes and is a great add-on to Yosemite via Tioga Pass (itself a seasonal, snow-gated road), plus Mono Lake and the US-395 corridor.
Pick your vehicle, line up the stops on the way in and out, and carry the whole route in your pocket.
