California’s Longest Hikes Pose Highest Injury Risks, Study Finds

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A new analysis of AllTrails data by Dennis Hernandez Injury Attorneys has identified the hiking trails in California that present the greatest risk of injury. The research analysed all strenuous-rated trails in the state with 200 or more reviews, using trail length as the primary indicator of risk: longer routes expose hikers to hazardous terrain, extreme elevation, and unpredictable conditions for greater distances.

California ranks 10th nationally for its proportion of challenging routes, with 24.3% of its 16,171 recorded trails classified as hard or strenuous. However, because California has more total listed hiking routes than any other state, it presents more potential for serious injury on trails than almost anywhere else in the US.

Top 10 California trails with the highest injury risk

Trail-specific hazards across the state

Cottonwood-Marble Canyon Loop

Sitting in Death Valley National Park, this 30.8-mile loop presents one of California’s most challenging backcountry routes due to difficult route-finding, steep canyon terrain, and limited water access. Daytime temperatures regularly exceed 120°F in summer, creating a severe risk of heat exhaustion or heatstroke. The trail requires scrambling or climbing experience, and AllTrails reviewers describe it as “extremely steep and tough.”

Grand Canyon of The Tuolumne

Located in Yosemite National Park, this 29.5-mile wilderness route passes through remote terrain where rescue access is severely limited, requiring hikers to ford icy rivers. Reviewers note that the trail is “brutal on the joints” and that “the descent and climbs were challenging.”

Timber Gap, Big Five-Little Five Lakes, and Monarch Lakes Loop

Spanning 28.7 miles in Sequoia National Park, this loop reaches elevations above 11,000 feet, crosses technical terrain, and combines exposed ridgelines with significant cumulative elevation gain. Reviewers note that the trek “required very strenuous hiking” and that the climb was “intense.” In 2021, the National Park Service reported that an unconscious hiker in the Big Five Lakes area required a helicopter rescue.

Mount Lyell

As the highest peak in Yosemite National Park at 13,114 feet, Mount Lyell features a 27.1-mile route involving glacier travel. Rated among the most technically demanding paths in the park, it requires equipment such as crampons, ice axes, and ropes. On AllTrails, 88% of hikers rated this trail as strenuous, with several reviewers noting they had to turn back due to lacking proper gear.

Mount Tyndall Trail

This 24-mile route in Inyo National Forest leads to a 14,018-foot summit. The trail requires technical Class 3 scrambling in a high-fall-risk environment with sustained exposure above the treeline and no maintained trail markings for much of the approach. 75% of reviewers rated it as strenuous, with some calling it “the hardest they have ever done.”

Cone Peak via Highway 1

Located in the Ventana Wilderness, this 23.1-mile path climbs one of the steepest coastal mountain faces in the contiguous US, rising from near sea level to 5,155 feet. Reviewers describe the trail as “crumbly” with “loose slopes” and warn of “poison oak and ivy on dangerous, overgrown paths.”

Mount Langley via Cottonwood Lakes Trail and New Army Pass Trail

Reaching the 14,026-foot summit of California’s 9th-highest peak, this 22.6-mile route features steep switchbacks, scrambling sections, and hazards from exposed ridges. Due to the high altitude, it presents a serious risk of altitude sickness. One reviewer noted facing poor conditions, writing they “would not attempt without alpine equipment.”

Mount Whitney Trail

This 21.7-mile route in Inyo National Forest leads to the highest peak in the contiguous US at 14,505 feet. Attempted by roughly 30,000 people annually, the route has a documented history of fatalities. Inyo County Search and Rescue regularly responds to incidents in the Whitney Basin caused by weather, altitude, and terrain. Hikers frequently report suffering from altitude sickness, and reviewers emphasise that “ice axes, crampons, and microspikes are crucial.”

Skyline Route: Cactus to Clouds

Situated in Mount San Jacinto State Park, this 19.6-mile path involves over 10,000 feet of elevation gain. AllTrails reviewers call the trail “brutal” and “a challenge”. California State Parks has temporarily closed the route on multiple occasions due to extreme heat, including a July 2024 closure following multiple rescue operations for heat exhaustion and dehydration.

Cottonwood Lakes Campground to Mount Langley

Rounding out the top 10, this 19.5-mile route through the John Muir Wilderness leads to the 14,026-foot summit. The high-altitude terrain carries persistent risks of altitude sickness and sudden weather changes, with reviewers highlighting “serious wind” and noting the hike is “not for the faint of heart.”

Expert insights and safety recommendations

Hernandez, commented on the unique risks faced by hikers in the state: “California has more total listed hiking routes than any other state in the country, which creates a lot of opportunities for hikers to find themselves in challenging positions. A lot of these trails are remote, which means that a minor injury could become more serious when help is hours away and cell service is unavailable. What makes California unique is the sheer variety of hazards across its trail network, from Death Valley heat to Sierra altitude to coastal exposure, all within a single state.”

“Many hikers think of falls as the biggest risk, but search-and-rescue teams regularly respond to dehydration, exhaustion, altitude illness, navigation errors, and situations where people simply underestimate how difficult a route will be. In Yosemite, for example, lower-extremity injuries from slips and falls, dehydration and exhaustion, and hikers becoming lost or stranded are among the most common reasons for rescues.”

“Hikers should download offline maps, check recent trail-condition reports, and identify turnaround points before they start. This can prevent small problems from becoming emergencies. On high-elevation routes, carrying a lightweight insulating layer and headlamp even for a day hike can make a significant difference if weather changes or progress is slower than expected. Sharing your planned route and expected return time with someone who is not on the hike is another simple step that can dramatically speed up rescue efforts if something goes wrong.”

Experts advise thorough preparation before attempting these demanding routes, including checking weather forecasts, carrying proper equipment, and informing others of planned travel details.

States with the highest percentage of strenuous trails