The North Bridge, often colloquially called the Old North Bridge, is a historic site in Concord, Massachusetts, spanning the Concord River. On April 19, 1775, the first day of the American Revolutionary War, provincial minutemen and militia companies numbering approximately 400 engaged roughly 90 British Army troops at this location. The battle was the first instance in which American forces advanced in formation on the British regulars, inflicted casualties, and routed their opponents. It was a pivotal moment in the Battles of Lexington and Concord and in American history. The significance of the historic events at the North Bridge inspired Ralph Waldo Emerson to refer to the moment as the "shot heard round the world".
There were at least eight iterations of the North Bridge constructed over four centuries. The current wooden pedestrian bridge, an approximate replica of the bridge that stood at the time of the battle, was built in 1956 and extensively restored in 2005. The bridge and the surrounding 114 acres of land make up what is known as the North Bridge unit of Minute Man National Historical Park, which is managed by the National Park Service. It is a popular tourist destination.