Madison Boulder Natural Area

This park is unstaffed but is open to the public year-round at no charge. 

Please be reminded that no comfort stations are available and all items (including trash) must be carried out with you when you leave.

Should an emergency arise during your visit, please call 911 for assistance.


Madison Boulder is the largest known 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 17-acre site was acquired by the state of N.H. in 1946. In 1970 Madison Boulder was designated a National Natural Landmark by the U.S. Department of the Interior because the enormous erratic, "is an outstanding illustration of the power of an ice sheet to pluck out very large blocks of fractured bedrock and move them substantial distances."

Picnic tables are available.

Are pets allowed at Madison Boulder Natural Area? Pets are permitted in the park. See NH State Parks Pets Policy for more information.