Gratiot (/ˈɡrætʃᵻt/) is a town in Lafayette County, Wisconsin, United States. The population was 653 at the 2000 census. The Village of Gratiot is located within the town. The unincorporated community of Riverside is also located in the town. The unincorporated community of Dunbarton is also partially in the town.
According to the United States Census Bureau, the town has a total area of 54.3 square miles (140.7 km²), all of it land.
As of the census of 2000, there were 653 people, 237 households, and 179 families residing in the town. The population density was 12.0 people per square mile (4.6/km²). There were 258 housing units at an average density of 4.8 per square mile (1.8/km²). The racial makeup of the town was 99.85% White and 0.15% Black or African American. 0.00% of the population were Hispanic or Latino of any race.
There were 237 households out of which 39.2% had children under the age of 18 living with them, 68.4% were married couples living together, 3.8% had a female householder with no husband present, and 24.1% were non-families. 21.9% of all households were made up of individuals and 11.4% had someone living alone who was 65 years of age or older. The average household size was 2.74 and the average family size was 3.19.