Jonathan Alder High School is an NCA accredited public high school located in Plain City, Ohio.

The school, as well as the district, are named after Jonathan Alder, the first white settler in Madison County.

[5] In Union County the district includes the rest of Plain City and most of the New California census-designated place.

[6] In Franklin County the district includes a portion of Dublin.

The original Jonathan Alder High School was built at 6440 Kilbury-Huber Rd., and was turned into a Junior High School when the new building was built.