Founded in 1819, Simpson County is one of 120 counties in the state of Kentucky. Historically, Simpson County was formed from Allen County, Logan County and Warren County. The city of Franklin is the county seat. With FIPS code of 213, Simpson County has a population of 19,718 and area of 236 square miles (611 km2).
List of all cities in Simpson County, KY alphabetically
| City/Town | Postal Code | Area Code |
| Franklin, KY | 42134 | 270 |
| 42135 | 270 |