The museum was opened in 1991 after a rare copy of the Declaration of Independence known as a Dunlap Broadside was found in the Ladd-Gilman house, 200 years after its arrival in Exeter.

[1] The Society of the Cincinnati, owners of the house, enlisted Sotheby's to explore a sale of the document, but that effort was halted when the State of New Hampshire raised questions about ownership.

The Ladd-Gilman House was the home of an 18th-century merchant family whose members played key roles in the birth of the United States.

Eldest son John Taylor Gilman read the Declaration of Independence to the citizens of Exeter in 1776 and later became New Hampshire governor for 14 non-consecutive terms between 1794 and 1805, and then again in 1813 to 1816.

In 1947, Martha Foster Stearns, a preservationist and Colonial Dame, proposed to restore the tavern, in exchange for a long-term residential lease.

Interior restoration began in 2006, after receiving a grant from New Hampshire's Land and Community Heritage Investment Program.

[4] The museum's collection of historical artifacts includes the Dunlap Broadside, two rare draft copies of the U.S. Constitution and a Badge of Military Merit (the original Purple Heart), awarded by General George Washington to soldiers demonstrating extraordinary bravery.

[8] In 1985, the Broadside of the Declaration of Independence was found in the upstairs floorboards when electricians were wiring a security system for the house.

[10] The broadside is displayed once a year on the third Saturday of July during the museum's American Independence Festival, that commemorates the arrival of the document and the reading by John Taylor Gilman.

The museum hosts a variety of public programs; the largest is the American Independence Festival, held annually during July.