Madison Boulder

The Madison Boulder is one of the largest known glacial erratics in North America and among the largest in the world; it is preserved in the 17 acre Madison Boulder Natural Area in Madison, New Hampshire. The boulder is a huge granite rock measuring 83 ft in length, 23 ft in height above the ground, and 37 ft in width. It weighs upwards of 5000 ST. A part of the block is buried, probably to a depth of 10 to 12 ft. It was acquired by the state from the Kennett family in 1946. In 1970, Madison Boulder was designated as a National Natural Landmark by the National Park Service.