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.
According to the United States Census Bureau, the town has a total area of 86.6 square miles (224.2 km), of which 85.1 square miles (220.5 km) are land and 1.4 square miles (3.7 km), or 1.64%, are water. The western boundary of Ellisburg is Lake Ontario, and the south town line is the border of Oswego County.
Interstate 81 passes through the east side of the town. U.S. Route 11 runs parallel to and just east of the interstate. New York State Route 3, a north-south highway, runs down the west side of Ellisburg. New York State Route 193, an east-west highway, intersects north-south highway New York State Route 289 at Ellisburg village.
As of the census of 2000, there were 3,541 people, 1,269 households, and 961 families residing in the town. The population density was 41.5 people per square mile (16.0/km²). There were 1,781 housing units at an average density of 20.9 per square mile (8.1/km²). The racial makeup of the town was 97.85% White, 0.40% Black or African American, 0.48% Native American, 0.37% Asian, 0.03% Pacific Islander, 0.37% from other races, and 0.51% from two or more races. Hispanic or Latino of any race were 1.04% of the population.
There were 1,269 households out of which 38.5% had children under the age of 18 living with them, 62.3% were married couples living together, 8.4% had a female householder with no husband present, and 24.2% were non-families. 19.0% of all households were made up of individuals and 9.0% had someone living alone who was 65 years of age or older. The average household size was 2.77 and the average family size was 3.16.
In the town, the population was spread out with 29.5% under the age of 18, 7.2% from 18 to 24, 29.6% from 25 to 44, 21.4% from 45 to 64, and 12.4% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 99.3 males. For every 100 females age 18 and over, there were 98.3 males.
The median income for a household in the town was $38,112, and the median income for a family was $40,903. Males had a median income of $31,184 versus $23,162 for females. The per capita income for the town was $17,102. About 10.9% of families and 13.6% of the population were below the poverty line, including 21.3% of those under age 18 and 6.7% of those age 65 or over.