Ellisburg is a town in Jefferson County, New York, United States. The population was 3,474 at the 2010 census. The town is in the southwestern corner of the county and is south of Watertown. Ellisburg is named after early European-American landowners. The town contains a village also called Ellisburg.
The area of the present-day town was visited by Samuel de Champlain and other French explorers and missionaries in the 17th century. Prehistoric remains show evidence of indigenous occupation for thousands of years prior to European encounter. The St. Lawrence Iroquoians had villages along the upper St. Lawrence River in the late 1500s. Further south along the Great Lakes, the Five Nations of the Iroquois Confederacy controlled territory.
Most of the Iroquois nations allied with the British during the American Revolutionary War. As a result of Great Britain's defeat, the United States forced the Iroquois to cede most of their territory in present-day New York, and the nations were resettled in Canada on reserves allocated by Great Britain.
Following the war, New York State made five million acres available for public purchase; land speculators bought large tracts of land for redevelopment. As part of such postwar development, Alexander Macomb bought thousands of acres in Macomb's Purchase. Thousands of migrants from New England flooded into upstate and western New York in the postwar years. Marvel and Lyman Ellis purchased the Town land from Macomb's Purchase and first settled around 1797 near Ellisburg village. Originally it was called "Ellisburgh."
When President Thomas Jefferson established the embargo against trade with Great Britain prior to the War of 1812, it adversely affected the thriving trade among the towns in upstate New York and Canada. The US Navy built and operated a major shipyard employing 3,000 workers at nearby Sackets Harbor, New York on Lake Ontario during the war. In 1814 during the War of 1812, a British invasion force was defeated at the Battle of Big Sandy Creek.
Settlers and developers had expected upstate New York to thrive due to trade with Canada. Following the War of 1812, the construction and opening of the Erie Canal through the Mohawk River Valley drew development westward, as New York City became linked with the commodities shipped from the Great Lakes area and Midwest. Towns of Jefferson County generally were bypassed by such western development, and many of their young people migrated west from the mid-nineteenth century. Watertown became a major industrial city at the turn of the twentieth century, due to its factories being powered by the change in grade on the river; it had a high number of millionaires per capita in those years.
The community of Belleville incorporated as a village. The community of Mannsville was incorporated as a village in 1879. Ellisburg village was incorporated in 1895. In 1930, Belleville abandoned its status as a village.