Oswegatchie is a town in St. Lawrence County, New York, United States. The population was 4,397 at the 2010 census. The name reportedly means “Black water” in the aboriginal language. It is on the northern border of the county and is adjacent to the city of Ogdensburg.
According to the United States Census Bureau, the town has a total area of 71.4 square miles (185 km), of which, 65.8 square miles (170 km) of it is land and 5.5 square miles (14 km) of it (7.76%) is water.
The Oswegatchie River flows through the town, defining part of the south town line. The northwest town line is defined by the St. Lawrence River, and is an international border with Canada.
New York State Route 812 is a north-south highway. New York State Route 37 is a highway on the south bank of the St. Lawrence River. New York State Route 68 is by the northeast town line.
As of the census of 2000, there were 4,370 people, 1,508 households, and 1,091 families residing in the town. The population density was 66.4 people per square mile (25.6/km²). There were 1,896 housing units at an average density of 28.8 per square mile (11.1/km²). The racial makeup of the town was 98.49% White, 0.30% African American, 0.34% Native American, 0.32% Asian, 0.02% Pacific Islander, 0.02% from other races, and 0.50% from two or more races. Hispanic or Latino of any race were 0.30% of the population.
There were 1,508 households out of which 35.1% had children under the age of 18 living with them, 58.0% were married couples living together, 9.5% had a female householder with no husband present, and 27.6% were non-families. 20.8% of all households were made up of individuals and 9.5% had someone living alone who was 65 years of age or older. The average household size was 2.69 and the average family size was 3.09.
In the town, the population was spread out with 26.1% under the age of 18, 6.2% from 18 to 24, 27.5% from 25 to 44, 23.8% from 45 to 64, and 16.5% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 91.1 males. For every 100 females age 18 and over, there were 87.1 males.
The median income for a household in the town was $36,700, and the median income for a family was $39,459. Males had a median income of $31,096 versus $23,365 for females. The per capita income for the town was $16,236. About 8.5% of families and 11.6% of the population were below the poverty line, including 15.8% of those under age 18 and 10.3% of those age 65 or over.