The Village of Waterloo is mostly in the Town of Waterloo, but the part south of the Cayuga-Seneca Canal of the village is in the Town of Fayette and a small portion in the south-east corner of the village is in the Town of Seneca Falls. Waterloo is east of Geneva.
In 1966, Waterloo was officially designated the "Birthplace of Memorial Day." It also holds the Memorial Day Museum.
Waterloo is located in between the two main Finger Lakes. Seneca Lake and Cayuga Lake. (See Cayuga Lake and Seneca Lake.)
As of the census of 2000, there were 5,111 people, 1,939 households, and 1,285 families residing in the village. The population density was 2,439.3 people per square mile (939.7/km²). There were 2,050 housing units at an average density of 978.4/sq mi (376.9/km²). The racial makeup of the village was 97.61% White, 0.82% Black or African American, 0.12% Native American, 0.49% Asian, 0.18% from other races, and 0.78% from two or more races. Hispanic or Latino of any race were 1.17% of the population.
There were 1,939 households out of which 31.8% had children under the age of 18 living with them, 48.5% were married couples living together, 14.0% had a female householder with no husband present, and 33.7% were non-families. 28.1% of all households were made up of individuals and 15.4% had someone living alone who was 65 years of age or older. The average household size was 2.47 and the average family size was 3.01.
In the village the population was spread out with 24.5% under the age of 18, 6.6% from 18 to 24, 26.9% from 25 to 44, 21.4% from 45 to 64, and 20.5% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 84.9 males. For every 100 females age 18 and over, there were 81.8 males.
The median income for a household in the village was $33,571, and the median income for a family was $41,725. Males had a median income of $34,911 versus $23,385 for females. The per capita income for the village was $16,538. About 7.2% of families and 12.1% of the population were below the poverty line, including 19.9% of those under age 18 and 9.3% of those age 65 or over.