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 (6.9 ha) Madison Boulder Natural Area in Madison, New Hampshire.^[4] The boulder is a huge granite rock measuring 83 feet (25 m) in length, 23 feet (7.0 m) in height above the ground, and 37 feet (11 m) in width. It weighs upwards of 5,000 short tons (4,500,000 kg). A part of the block is buried, probably to a depth of 10 to 12 feet (3.0 to 3.7 m).^[4] It was acquired by the state from the Kennett family in 1946.^[3] In 1970, Madison Boulder was designated as a National Natural Landmark by the National Park Service.^[5]

Madison Boulder Natural Area
The Madison Boulder as photographed in 1922
Madison Boulder Location in New Hampshire
Location	Madison, New Hampshire, United States
Coordinates	43°55′53″N 71°10′04″W[1]
Area	17 acres (6.9 ha)[2]
Elevation	512 feet (156 m)[1]
Established	1946[3]
Administered by	New Hampshire Division of Parks and Recreation
Designation	National Natural Landmark
Website	Madison Boulder Natural Area

See also

• List of individual rocks