The Second Battle of Fort Ticonderoga, occurring between July 2-6, 1777, resulted in a British victory as General John Burgoyne's forces seized the fort, forcing the American garrison under General Arthur St. Clair to evacuate, marking a key event in the Saratoga Campaign. Lieutenant General John Burgoyne's 8,000-man army occupied high ground above the fort, and nearly surrounded the defenses. These movements precipitated the occupying Continental Army, an under-strength force of 3,000 under the command of General Arthur St. Clair, to withdraw from Ticonderoga and the surrounding defenses. Some gunfire was exchanged, and there were some casualties, but there was no formal siege and no pitched battle. Burgoyne's army occupied Fort Ticonderoga and Mount Independence, the extensive fortifications on the Vermont side of the lake, without opposition on 6 July. Advance units pursued the retreating Americans. On 1 July, General St. Clair was still unaware of the full strength of Burgoyne's army, which lay just 4 miles away. On the morning of 2 July, St. Clair decided to withdraw the men occupying the defense post at Mount Hope, which was exposed and subject to capture. On 4 July, the Americans held a quiet celebration with some toasts to commemorate the previous year's Declaration of Independence. That night the British lost their element of surprise when some Indians lit fires on Sugar Loaf, alerting the Americans to their presence there. On the morning of 5 July, St. Clair held a war council in which the decision was made to retreat. Since their position was completely exposed, they delayed departure until nightfall, when their movements would be concealed. All possible armaments, as well as invalids, camp followers, and supplies were loaded onto a fleet of more than 200 boats that began to move up the lake toward Skenesboro, accompanied by Colonel Pierse Long's regiment.

Owing to a shortage of boats, four invalids were left behind, as were the very largest cannons and a variety of supplies—everything from tents to cattle. The rest of the army crossed to Mount Independence and headed down the Hubbardton road, which Riedesel's forces had not yet reached. A handful of men were left at the pontoon bridge with loaded cannons to fire on British attempts to cross it, but they were drunk when the British arrived the next morning. The British occupied the forts without firing a single shot, and detachments from Fraser's and Riedesel's troops set out in pursuit of the retreating Americans on the Hubbardton road, while Burgoyne hurried some of his troops up the lake toward Skenesboro. The withdrawal from Ticonderoga was hurried, but was a part of the American defensive strategy adopted by Schuyler in response to the British Saratoga Campaign. Fraser's pursuit resulted in the Battle of Hubbardton as they caught up with the rear guard. St. Clair, meanwhile, brought most of his men to join forces with Schuyler at Fort Edward, and prepare for the Battle of Saratoga. Ticonderoga did not substantially delay Burgoyne's advance, but he did leave several regiments and much of his Canadian force as a garrison. Fort Ticonderoga was an important symbol for the Americans, who expected that the fort would keep the redcoats out of the northern colonies, particularly in view of the winter spent improving the fortifications. St Clair’s abrupt retreat caused alarm and outrage. The political and public outcry after the withdrawal was significant. The Congress was appalled, and criticized both Schuyler and St. Clair for the loss.