At the same time of the Lexington Campaign, steps were taken to send an expedition against British-held Fort Ticonderoga on Lake Champlain, a strategic post well-supplied with artillery and military stores much needed by the American forces investing Boston. Early on May 10th, a New England force of some 80 men led by Cols. Ethan Allen of Vermont and Benedict Arnold of Connecticut surprised the British garrison of about 40 men, which surrendered without a fight.
Following this success, Allen seized Crown Point on May 12th and Arnold temporarily occupied St. John's, a fort across the Canadian border, on May 16th. Subsequently, a large part of the 100 cannon and substantial military stores captured at Ticonderoga were laboriously hauled overland to Boston under the direction of Maj. Gen. Henry Knox, of Washington's artillery, to supply the army besieging the city.