Lost River Gorge and Boulder Caves

Lost River runs through Kinsman Notch, a pass carved and steepened by glaciers during the last ice age. As the ice advanced and retreated it plucked and dumped enormous blocks of granite, and it was this jumble of fallen and stacked boulders that created the gorge's signature feature: the river running underneath the rocks rather than over open ground.

The caves here are not solution caves dissolved out of limestone but boulder caves, the gaps and passages left between and beneath the giant blocks. That is why they twist, narrow, and open unpredictably, and why some, like the famous Lemon Squeezer, are genuinely tight. The moving water has worn potholes and smoothed the stone over thousands of years, adding waterfalls and pools along the descent.

The visit follows a boardwalk and stairway that loops down one side of the gorge and back up the other, roughly three-quarters of a mile in all, with the river, waterfalls, and boulder piles alongside. Interpretive signs explain the geology and the forest, and the shaded, damp microclimate keeps ferns and moss lush over every surface.

Along the way, marked side trips lead into the boulder caves, each with a name and a personality, some easy, some requiring a real crawl. Every cave is optional, with a bypass on the main boardwalk, so families can mix and match, sending the kids through the squeeze while others meet them on the far side.

The site also keeps a few gentler attractions up top, including a nature garden and a suspension bridge, making it easy to fill a relaxed couple of hours.

Lost River has welcomed visitors for well over a century and is owned and protected by a New Hampshire forest conservation organization, which keeps the land undeveloped around it. That long history makes it one of the classic stops on a White Mountains road trip, in the same tradition as the region's scenic notches and auto roads.

Its location in Kinsman Notch puts it within easy reach of Lincoln and North Woodstock, the Kancamagus Highway, and Franconia Notch, so it slots neatly into a day of mountain sightseeing.

Late spring opens the season with the river running high and loud from snowmelt, the waterfalls at their fullest.

Summer is the busiest and best time for the caves, when the cool gorge is a welcome escape from the heat and everything is green and dripping.

Fall wraps the gorge in color and thinner crowds, a beautiful time to walk the boardwalk before the seasonal closing.

In winter the attraction closes and the notch belongs to snow and ice, though the surrounding mountains stay open for skiing and snowshoeing.

The closest Boutel™ stays, so you can turn this stop into an overnight. Each is an independently owned, editorially selected place to stay.