Charleston Township was named for one of its founders, Charles Morton.

[3] The township contains fourteen cemeteries: Adkins, Chambers, Cossel, Fudge, Huckaba, Kickapoo, Lumbrick, Mound, Old Charleston, Roselawn, Salem, Stoner, Unity and Yocum.

As of the 2020 census[1] there were 19,313 people, 8,615 households, and 4,475 families residing in the township.

The racial makeup of the township was 81.17% White, 7.62% African American, 0.26% Native American, 2.36% Asian, 0.12% Pacific Islander, 3.54% from other races, and 4.93% from two or more races.

33.40% of all households were made up of individuals, and 9.00% had someone living alone who was 65 years of age or older.