Maineville is a village in Warren County, Ohio, United States. The population was 975 at the 2010 census.
Maineville was incorporated as a village on March 23, 1850. The village derives its name from Maine, the native state of a large share of its first settlers. A post office was established at Maineville in 1854.
Maineville is located at 39°19′1″N 84°13′23″W (39.316998, -84.222924).
According to the United States Census Bureau, the village has a total area of 1.37 square miles (3.55 km2), all land.
As of the census of 2010, there were 995 people, 401 households, and 266 families living in the village. The population density was 711.7 inhabitants per square mile (274.8/km2). There were 422 housing units at an average density of 308.0 per square mile (118.9/km2). The racial makeup of the village was 97.6% White, 0.5% African American, 0.1% Native American, 0.4% Asian, 0.2% from other races, and 1.1% from two or more races. Hispanic or Latino of any race were 0.8% of the population.
There were 401 households, of which 31.9% had children under the age of 18 living with them, 51.1% were married couples living together, 8.5% had a female householder with no husband present, 6.7% had a male householder with no wife present, and 33.7% were non-families.