The Battles of Lexington and Concord on April 19, 1775, signaled the start of the American Revolutionary War, and Stark returned to military service. On April 23, 1775, Stark accepted a Colonelcy in the New Hampshire Militia and was given command of the 1st New Hampshire Regiment and James Reed of the 3rd New Hampshire Regiment, also outside of Boston. As soon as Stark could muster his men, he ferried and marched them south to Boston to support the blockaded rebels there. He made his headquarters in the confiscated Isaac Royall House in Medford, Massachusetts.