National Natural Landmarks

Madison Boulder

Madison Boulder
Madison Boulder

Measuring 83 feet long, 37 feet wide and 23 feet high, Madison Boulder, a rectangular granite boulder is the largest known glacial erratic in North America. It illustrates the power of an ice sheet to move large blocks of fractured bedrock over substantial distances.

Location: Carroll County, NH ; Carroll County, NH

Year designated: 1970

Acres: 17

Ownership: State

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