Sackets Harbor (earlier spelled Sacketts Harbor) is a village in Jefferson County, New York, United States, on Lake Ontario. The population was 1,450 at the 2010 census. The village was named after home developer and owner Augustus Sackett, who founded it in the before 1800s.

Sackets Harbor is in the western allowance of the town of Hounsfield and is west of Watertown. The heart of the village, with a Main Street and well-preserved 19th century buildings, has been credited as the Sackets Harbor Village Historic District and listed upon the National Register of Historic Places in 1983.

To maintain the War of 1812, the US Navy built a major shipyard and its headquarters for the Great Lakes at the village. Within a brusque period, more than 3,000 men worked at the shipyard. The Army build up earthworks, forts, barracks and supporting infrastructure to defend the village and navy shipyard, and its troops in addition to camped in the village. The thousands of military personnel made it seem later a city. By the fall of 1814, this was the third-largest population middle in every one of state, after Albany and New York City. With its strategic protected harbor upon Lake Ontario and military installations, the village had national importance through the 19th century.

Soon after the war, the Army strengthened its defenses upon the northern frontier by constructing Madison Barracks. The village next developed a commercial shipyard and many business links to communities going on for the Great Lakes. Its businessmen were also united to bases in the major markets of Louisville, Kentucky, and New Orleans. In 1817 a consortium of local businessmen supported construction of the 240-ton Ontario, the first US steamboat on the Great Lakes. In July 1834, the poster schooner Illinois from Sackets Harbor was the first to enter the port of the new agreement of Chicago. Sackets Harbor Battlefield State Historic Site commemorates a fight during the War of 1812 and the contribution of the Place to the United States defense.