A map of Fort Ticonderoga in 1759.
Fort Ticonderoga, also known as Fort Carillon, was a star fort built by the French in the late 1750s during the French and Indian War at a choke point in the Champlain Valley between Lake George and Lake Champlain. The fort served as a barrier to any British advance up the Champlain Valley to the city of Montreal in Quebec. In July 1758 a British force of 16,000 men under General James Abercrombie was defeated by less than 4,000 French defenders at the Battle of Fort Carillon. The following year, a British force of 11,000 men captured Fort Carillon in July after its garrison of 400 Frenchmen abandoned it. The British renamed it Fort Ticonderoga.
The British allowed Fort Ticonderoga to fall into disrepair in the years after the 1763 Treaty of Paris ended the war. Following the outbreak of the North American Rebellion in April 1775, a force of rebel militia under Ethan Allen and Benedict Arnold took Fort Ticonderoga, transferred its captured artillery to the Siege of Boston, and used the fort as the jumping-off point for an invasion of Quebec. After the rebel defeat at Quebec City in December, General Guy Carleton mounted a counteroffensive that drove the rebels out of Quebec. However, it was not until General John Burgoyne's advance on New York Province in 1777 that the British recaptured Fort Ticonderoga from the rebels.
After the rebel surrender ended the Rebellion in 1778, Fort Ticonderoga was again allowed to fall into disrepair.