On this day in 1776, a British fleet under Sir Guy Carleton defeats 15 American gunboats under the command of Brigadier General Benedict Arnold at the Battle of Valcour Island on Lake Champlain, in what is now Clinton County, New York.

Although nearly all of Arnold's ships were destroyed, it took more than two days for the British to subdue the Patriot naval force, delaying Carleton's campaign and giving the Patriot ground forces adequate time to prepare a crucial defense of New York.

One year earlier, during the Patriots' unsuccessful campaign to take Canada, Carleton, the royal governor general of Canada, had managed to escape Patriot General Richard Montgomery's early successful attacks during the summer and autumn. He snuck into Quebec City, organized 1,800 men for the city's defense, and prepared to wait out the Patriot siege. The Patriots, facing a deadline as their troops' enlistments expired at the end of the year, fired arrows over the city walls on December 7. The arrows carried letters demanding Carleton's surrender. When Carleton did not acquiesce, the Americans began a bombardment of the city with Montgomery's cannon on December 8. They then attempted a disastrous failed assault on December 31, in which Montgomery was killed and Arnold seriously wounded. The action around Valcour Island was the final stage of Carleton's effort to drive Arnold from Canada, once and for all.

Arnold was considered a Patriot hero for his bravery in the siege of Quebec, and earlier during the Patriot capture of Fort Ticonderoga, New York, on May 10, 1775. Arnold, however, did not feel that he had received sufficient accolades for his efforts, and, while serving as commander of West Point in 1780, agreed to surrender the important Hudson River fort to the British for a bribe of £20,000. The plot was discovered after British spy John Andre was captured while carrying incriminating papers, forcing Arnold to flee to British protection. He then joined the British in their fight against the country that he had once so valiantly served.

Arnold died in London in 1801. To Americans, his name is still synonymous with the word "traitor."