In August 2025 I backpacked about fifty miles of the High Sierra, starting at the Onion Valley trailhead and finishing at Whitney Portal. Of every trip on my list, it's the one that kept me at altitude the longest.
The route
- Onion Valley over Kearsarge Pass: the way in, climbing out of the Owens Valley side to join the John Muir Trail.
- South on the John Muir Trail: including Forester Pass, one of the highest passes on the trail.
- Trail Crest at about 13,600 feet: a long switchback climb, then the descent to Whitney Portal.
The totals come out to roughly 50 miles and 12,000 feet of elevation gain. Those are published route figures, not GPS numbers, but they're close enough to plan around.
What made it hard
Altitude was the story of the whole trip. Most backpacking routes climb to a pass and drop back down. This one stays high for days, with multiple passes over 13,000 feet. Everything takes more effort when the air is that thin, from the climbs themselves to sleeping and eating well enough to recover.
The other challenge was carrying enough. There are long stretches between resupply points in this part of the Sierra, so the pack is heaviest exactly when the trail is highest.
What I'd tell someone planning it
- Respect the altitude. Build in time to acclimatize, and plan your days around how you'll feel at 12,000 feet, not at sea level.
- Plan food and water carefully. Weight matters more than usual when every climb is above treeline.
- Sort out permits early. Popular High Sierra trailheads and the Whitney area are permit-controlled.
It's the trip I'd point to if someone asked what the High Sierra is really like. Shorter trip notes for this route and others are in my field notes.