French forces hold Fort Carillon against the British at Ticonderoga, New York.

Fort Carillon, presently known as Fort Ticonderoga, was constructed by Pierre de Rigaud de Vaudreuil, Governor of French Canada, to protect Lake Champlain from a British invasion. Situated on the lake some 15 miles (24 km) south of Fort Saint Frédéric, it was built to prevent an attack on Canada and slow the advance of the enemy long enough for reinforcements to arrive.Assigned to remedy Fort Saint Frédéric's inability to resist a constant British threat to the south, French King's Engineer Michel Chartier de Lotbinière began construction of Fort Carillon where Lake George, at that time called Lac Saint Sacrement, joins Lake Champlain by the La Chute river. Construction began in October 1755.