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.