Mount Diablo Six Peaks Challenge

The day after Christmas, and this time the Six Peaks loop got a twist: instead of the usual start from Mitchell Canyon, we parked at the free Regency Drive trailhead on Diablo's north side and worked the loop from there — Mount Olympia first, then North Peak, then down to the main summit, followed by Eagle Peak, Twin Peaks, and Mitchell Rock to close it out. The longer approach pushed the day out to around 17 miles, more than any previous lap of this loop.

Cold, wet, and socked in the whole way — steady rain, thick fog, and a wind that never let up, with visibility dropping to almost nothing along some of the exposed ridge stretches between peaks. Diablo's summit sign and the register disc at the top were about the only calm moment to stop, get out of the wind for a minute, and take stock before pushing on to the last three summits.

Eagle Peak's narrow rock ridge and the switchbacks up to Twin Peaks were slick with rain by the time we got there, and Mitchell Rock's rust-colored outcrop closed out the day looking almost black in the wet, low light. A genuinely miserable-in-the-best-way version of this loop — a different trailhead, the worst weather any of these ascents has seen yet, and still great company the entire way around.

Back for another lap of the Diablo Six Peaks loop, and at this point it's become one of my go-to training days — a genuinely great way to build fitness and elevation legs before bigger objectives elsewhere. Same demanding circuit out of Mitchell Canyon: Mount Diablo, North Peak, Eagle Peak, Mount Olympia, Mitchell Rock, and Twin Peaks, all strung together in one long day.

A thick marine layer had pushed in below the ridgelines for most of the day, turning the lower valleys into a solid bank of cloud while the summits stayed in clear, hazy light above it — Eagle Peak's stone lookout and Diablo's summit tower both stood out sharply against the fog rolling through the canyons below. Later in the day, as the loop wound down through the drier, golden hills on the way to Twin Peaks and Mitchell Rock, the clouds burned off and the more familiar sun-baked Diablo landscape took over.

There's a reason this loop keeps earning repeat visits — six real summits, close to 15 miles, and nearly 4,750 feet of gain packed into a single push, with enough variety in terrain and views to never feel repetitive even after multiple trips around it. As pure training for whatever's next on the list, it's hard to beat.

Third time doing the full Diablo Six Peaks loop, just under a year after the second. Same brutal circuit out of Mitchell Canyon — Mount Diablo, North Peak, Eagle Peak, Mount Olympia, Mitchell Rock, and Twin Peaks — but February instead of March meant a completely different landscape underfoot. The hills were that deep, saturated winter green they only hold for a few months a year out here, a big contrast from the drier gold-and-brown tones of the earlier attempts.

The climbing didn't get any easier with repetition — six summits in one loop still means constant up and down with almost no flat stretches to recover on — but knowing the route this well by now made it easier to pace the day and know exactly which climbs to save some energy for.

The evening light on the way down was the highlight of this trip — soft, hazy dusk color settling over layer after layer of green ridgeline as the sun dropped toward the Bay. Same six summits, same long day, but a completely different mountain in winter than it was the first two times around.

Back for the full Diablo Six Peaks loop four years after the first time — Mount Diablo, North Peak, Eagle Peak, Mount Olympia, Mitchell Rock, and Twin Peaks, same brutal circuit out of Mitchell Canyon. The route hadn't gotten any easier with time, but knowing it well by now made the pacing a lot more comfortable than that first attempt back in 2017.

Six summits in one loop still means constant climbing and descending with almost no flat ground to recover on, and Olympia's steep pitch and Eagle Peak's narrow rock ridge were just as demanding as always. A good reminder of why this loop earned its reputation as one of the toughest single-day routes on the mountain.

Back for the full Six Peaks loop just under eight months after the first attempt — Mount Diablo, North Peak, Eagle Peak, Mount Olympia, Mitchell Rock, and Twin Peaks, same demanding circuit out of Mitchell Canyon. Storm clouds hung low over the ridgelines most of the day, giving the whole loop a moodier, more dramatic feel than the drier spring version, with shafts of light breaking through onto the hillsides here and there.

Late fall meant golden, dry grass everywhere and noticeably more wildlife on the move — a pair of deer working a hillside in the distance, and a small flock of wild turkeys picking their way along the trail, not in any hurry to clear out of the way. A stretch of trail wrapped in fog near one of the ridgelines added yet another mood to an already varied day.

Six summits, nearly 16 miles, and close to 4,750 feet of gain — this loop doesn't get any easier the second time, but the variety of light and wildlife on this particular day made it feel like a completely different hike from the first.

This was my first time stringing together the local classic — sometimes called the Diablo "Six Peaks" challenge, even though purists will point out it's really five actual peaks and one very photogenic rock. Starting from Mitchell Canyon, the route strings together Mount Diablo, North Peak, Eagle Peak, Mount Olympia, Mitchell Rock, and Twin Peaks in a single long loop, climbing and descending repeatedly across ridgelines, talus, and chaparral for the better part of a day.

Mount Diablo itself is the anchor and the high point at 3,849 feet — the only stop on the route with a paved road and a visitor center, complete with an ice cream sandwich waiting at the summit store and a small sign marking the exact high point a short walk from the observation deck. Everything else on the loop is a completely different kind of summit: Eagle Peak narrows into a genuine knife-edge rock ridge with barely enough flat ground to stand on; Mount Olympia is short but relentlessly steep, one of the toughest sustained climbs in the whole park; North Peak is Diablo's rugged, road-less twin, nearly as tall but rarely visited; and Mitchell Rock closes things out as a rust-red outcrop of ancient pillow basalt, a completely different color and texture from everything else on the mountain.

Six summits in one day is a lot to ask of your legs, and the terrain never really lets up — loose rock, steep grades, and long exposed stretches with almost no shade the entire way. Nearly 15 miles and 4,700-some feet of gain later, I was hooked on this loop as one of the best full-value days anywhere on the mountain — oak woodland giving way to chaparral, grassy ridgelines giving way to knife-edge rock, and views swinging from the Bay and its bridges to the Sierra Nevada to the Central Valley and back, all in a single push out of Mitchell Canyon.