|The Madison Boulder|
Off Route 113
Madison, NH 03849
The Madison Boulder is the largest known glacial erratic in New England, and among the largest in the world. Madison Boulder is a huge granite rock measuring 83 feet in length, 23 feet in height above the ground, and 37 feet in width. It weighs upwards of 5,000 tons! A part of this roughly rectangular block is buried, probably to a depth of ten to twelve feet.
The Madison Boulder site was acquired by the state of N.H. in 1946 and designated a National Natural Landmark in 1970
A glacial erratic is a boulder that does not mirror the rock make-up of the area in which it sits, leading to the conclusion that it was deposited in the site by glacial action. It is speculated that the Madison Boulder was moved by the most recent glacier from a point some 20 miles away, perhaps farther.
Madison Boulder Natural Area is open to the public year-round at no charge. Picnic tables are available.