Mount Percival's cave route earns its Terrifying 25 designation not through exposure or height but through sheer physical awkwardness: just below the 2,200-foot summit, a signed junction splits the trail into a cliff route and a cave route, and hikers who take the caves must remove their packs and shimmy prone through gaps barely wide enough for a human body. The passages are formed by a jumble of massive granite boulders, with tiny openings at each end requiring hikers to lie flat and squeeze through. Between the squeezes, the route involves Class 2 to 3 scrambling on solid rock, using hands throughout. The segment covers about 1.8 miles with roughly 1,300 feet of gain, climbing through forested switchbacks before the terrain opens onto the ledge summit with views southeast toward Squam Lake.
The cave is not a true cavern but a void beneath car-sized boulders; the gaps are small enough that bulkier hikers may find them a genuine challenge. Descending through the caves is considered easier than descending the wooden ladders on the adjacent Mount Morgan Trail, making it the preferred downhill leg of the popular Morgan-Percival loop. Both trails share a trailhead on Route 113 near Holderness.
Wet rock raises the scrambling difficulty noticeably, and the boulder field holds ice and snow well into spring. Hikers who are not comfortable in confined spaces can take the cliff route to the same summit with no crawling required.
