Last year, Caroline Himbert set the unsupported fastest known time (FKT) of the John Muir Trail (JMT) in dramatic fashion. She passed out after extreme hallucinations, woke up, and managed to race on, beating the FKT on the 223-mile trail by just 8 minutes.
Himbert recently took on the JMT record again, this time beating it by a huge margin, cementing her status as one of the reigning crushers of the JMT.
What Is the John Muir Trail?
The John Muir Trail is one of California’s most scenic — and challenging — backpacking trails, crossing both Mt. Whitney and Yosemite Valley. Most hikers typically complete the trail in 2 to 3 weeks.
The route scales 10 passes in the High Sierra, making for a series of challenging ascents and descents. The total elevation gain on the route is 46,000 feet, and the total loss is 38,000 feet, demanding serious fitness.
Many elite ultra-runners have come to the JMT to test their mettle and try to nab an FKT. Fastest known times can be completed supported (with aid and resupplies from crew members) or unsupported (completely solo). Runners can take the route northbound or southbound; most people (including Himbert) go northbound so that the route’s highest point, Mt. Whitney, comes at the beginning and not the end.
JMT Record Broken Again
Himbert began her most recent attempt on July 28. Oddly enough, she was more anxious this time around than her first go.
“I was honestly way more nervous this year than last. There’s a lot of uncertainty covering over 220 miles alone in the mountains, and I carried plenty of scary lessons from my first attempt with me,” she said on Instagram.
On this attempt, she really had to fight through sleep deprivation. “Last year, I said yes when exhaustion convinced me to take a four-hour nap off trail,” she explained. “This year, after three nights with barely any sleep, I had plenty of imaginary friends encouraging me to lie down again. I was nodding off while hiking, but I knew where that decision had led before.”
Himbert’s grit and will paid off: She broke her own FKT by over 12 hours and got it down to under 4 days, finishing in 3 days, 16 hours, and 35 minutes.
Himbert’s History on the JMT
Himbert first traversed the JMT as a thru-hiker on the Pacific Crest Trail (PCT); all of the trail’s 223 miles fall on the landmark thru-hike. In August 2025, she set out to try to beat the women’s unsupported FKT on the route.
The attempt started off strong, but by day 3, she was in rough shape. The effects of sleep deprivation took their toll: At some points, she would walk backward on the trail instead of moving forward. She fell asleep for 5 hours, and her support team almost called search and rescue for her. She woke up, startled, and then sprinted to the finish, just barely beating the existing record.
Perhaps the other most notable change in this year’s run was what happened after. Last year, Himbert begged her friends to bring her a cold soda to drink after she finished. They brought her a Sprite Zero of all beverages, and Himbert was low-key furious. This year, she got a full-sugar Sprite and a liter of chocolate milk, appropriate celebratory beverages for an incredible PR.
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