Located near the town of Madison in New Hampshire, Madison Boulder is a massive 83-foot-long and 23-foot high granite rock that weighs more than 5,000 tons. The entire 17-acre area around it is developed to protect this National Natural Landmark, which "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," according to the US Department of the Interior. Madison Boulder is believed to be North America’s largest glacial erratic, a rock that was moved by glacier and deposited on an area of completely different type of rock. It was once a piece of a ledge of Conway Granite and was moved about 2 miles to its current location, where it now sits on a field of Concord Granite.

473 Boulder Rd, Madison, NH 03849, Phone: 603-227-8745

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