North Bridge Visitor Center (174 Liberty St. Concord MA.) is located in a brick mansion built in 1911 by descendents of the Buttrick family (Major John Buttrick was the colonial officer who first ordered his militia to fire upon British soldiers.), the North Bridge Visitor Center features a short video about the North Bridge fight, a bookstore and exhibits.
Among the exhibits in the park is a brass cannon, dubbed "The Hancock" in celebration of its storied past. In 1775, this cannon, recently smuggled out of Boston, was one of four brass cannons hidden in Concord and its recovery was one of General Gage's chief motives when he sent British troops to Concord on April 19, 1775. It is one display courtesy of the Bunker Hill Monument Association.
-GPS for North Bridge Visitor Center Parking Lot is: 42.471226, -71.353360