Jerome Township is one of the fourteen townships of Union County, Ohio, United States. The 2020 census found 9,504 people in the township. Parts of two municipalities are located in Jerome Township: the village of Plain City in the southwest, and the city of Dublin in the southeast. The unincorporated communities of Arnold, Jerome, and New California a…Jerome Township is one of the fourteen townships of Union County, Ohio, United States. The 2020 census found 9,504 people in the township. Parts of two municipalities are located in Jerome Township: the village of Plain City in the southwest, and the city of Dublin in the southeast. The unincorporated communities of Arnold, Jerome, and New California are also located within the township.