Northumberland is a town in Saratoga County, New York, United States. The population was 4,603 at the 2000 census. The name comes from a location in Great Britain.
According to the United States Census Bureau, the town has a total area of 32.9 square miles (85 km), of which, 32.3 square miles (84 km) of it is land and 0.6 square miles (1.6 km) of it (1.67%) is water.
The east town line is the border of Washington County and is marked by the Hudson River.
US Route 4 is a north-south highway by the Hudson River at the southeast corner of Northumberland. New York State Route 32 is a north-south highway that intersects New York State Route 50 at Gansevoort. US-4 and NY-32 are conjoined in Northumberland.
As of the census of 2000, there were 4,603 people, 1,593 households, and 1,264 families residing in the town. The population density was 142.3 people per square mile (54.9/km²). There were 1,717 housing units at an average density of 53.1 per square mile (20.5/km²). The racial makeup of the town was 98.09% White, 0.54% African American, 0.33% Native American, 0.28% Asian, 0.17% from other races, and 0.59% from two or more races. Hispanic or Latino of any race were 0.93% of the population.
There were 1,593 households out of which 44.3% had children under the age of 18 living with them, 67.1% were married couples living together, 7.8% had a female householder with no husband present, and 20.6% were non-families. 14.5% of all households were made up of individuals and 4.9% had someone living alone who was 65 years of age or older. The average household size was 2.88 and the average family size was 3.18.
In the town, the population was spread out with 30.0% under the age of 18, 5.8% from 18 to 24, 36.6% from 25 to 44, 20.2% from 45 to 64, and 7.3% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 101.5 males. For every 100 females age 18 and over, there were 99.6 males.
The median income for a household in the town was $51,559, and the median income for a family was $53,523. Males had a median income of $36,964 versus $28,185 for females. The per capita income for the town was $19,104. About 4.8% of families and 6.2% of the population were below the poverty line, including 9.1% of those under age 18 and 2.1% of those age 65 or over.