Lost River Reservation
Coordinates: 44°02′16″N 71°47′02″W / 44.03778°N 71.78389°W
The Lost River Reservation (also known as the Lost River Gorge & Boulder Caves) is a series of caves in the White Mountains in Woodstock, New Hampshire, United States. Located 5 miles (8 km) west of the village of North Woodstock on New Hampshire Route 112, Lost River Reservation is set in Kinsman Notch. One of the White Mountains' major passes, Kinsman Notch lies between Mount Moosilauke and Kinsman Ridge at just under 2,000 feet (600 m) above sea level. Lost River Reservation is owned by the Society for the Protection of New Hampshire Forests.
The Lost River is so-named because the brook draining the southern part of Kinsman Notch disappears below the surface in a narrow, steep-walled glacial gorge. The gorge is partially filled with immense blocks of granite, through the spaces of which the brook cascades along its subterranean course until it eventually emerges and joins the Pemigewasset River, which flows southward from Franconia Notch.