Frankfort is a village in Ross County, Ohio, United States, along the North Fork of Paint Creek. The village is located in Concord Township. The population was 1,084 at the 2020 census. Frankfort was originally called Oldtown, and under the latter name was laid out in 1816. A post office called Old Town was established in 1817, and the name was changeā¦Frankfort is a village in Ross County, Ohio, United States, along the North Fork of Paint Creek. The village is located in Concord Township. The population was 1,084 at the 2020 census. Frankfort was originally called Oldtown, and under the latter name was laid out in 1816. A post office called Old Town was established in 1817, and the name was changed to Frankfort in 1834. Frankfort was incorporated as a village in 1827.