The Old Barracks Museum, also known as Old Barracks, in Trenton, Mercer County, New Jersey, United States, is the only remaining colonial barracks in New Jersey. It is the last of five such barracks authorized by the colonial legislature in 1758 to house soldiers in the French and Indian War. It housed about 300 soldiers at a time. During the American Revolution, George Washington crossed the Delaware River to catch the Hessian garrison in Trenton by surprise. Following the American Revolution, the Trenton Barracks were used as a military hospital specializing in smallpox inoculations.
In 1902, members of the Daughters of the Revolution bought part of the building to preserve it. The state bought the other part and formed a museum in 1914 which continues to be open and supported by the State of New Jersey.The Museum is open to visitors year round, Monday - Saturday, and is known for the annual Battle of Trenton Reenactments on the Saturday following Christmas.