The Town of Peru is in the eastern part of the county and is south of Plattsburgh.
As of the census of 2000, there were 6,370 people, 2,309 households, and 1,777 families residing in the town. The population density was 80.3 people per square mile (31.0/km²). There were 2,510 housing units at an average density of 31.6/sq mi (12.2/km²). The racial makeup of the town was 97.22% White, 0.91% Black or African American, 0.08% Native American, 0.61% Asian, 0.16% from other races, and 1.02% from two or more races. Hispanic or Latino of any race were 0.85% of the population.
There were 2,309 households out of which 39.2% had children under the age of 18 living with them, 63.4% were married couples living together, 9.3% had a female householder with no husband present, and 23.0% were non-families. 18.1% of all households were made up of individuals and 7.5% had someone living alone who was 65 years of age or older. The average household size was 2.73 and the average family size was 3.07.
In the town the population was spread out with 28.3% under the age of 18, 6.5% from 18 to 24, 30.4% from 25 to 44, 23.2% from 45 to 64, and 11.5% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 94.6 males. For every 100 females age 18 and over, there were 90.8 males.
The median income for a household in the town was $39,051, and the median income for a family was $47,853. Males had a median income of $32,196 versus $23,984 for females. The per capita income for the town was $19,676. About 7.6% of families and 11.1% of the population were below the poverty line, including 14.3% of those under age 18 and 9.6% of those age 65 or over.