Brookville is a small city in northwestern Montgomery County, Ohio, United States.

Brookville was platted in 1850, and named for a small brook near the town site.

[5] According to the United States Census Bureau, the city has a total area of 3.82 square miles (9.89 km2), all land.

There were 2,684 housing units at an average density of 702.6 per square mile (271.3/km2).

31.3% of all households were made up of individuals, and 17% had someone living alone who was 65 years of age or older.

There were 2,326 housing units at an average density of 690.7 per square mile (266.7/km2).

30.4% of all households were made up of individuals, and 15.6% had someone living alone who was 65 years of age or older.