Founded on Nov 23, 1810, Jefferson County is one of 92 counties in the state of Indiana. Historically, Jefferson County was formed from Clark, Dearborn and Knox County. The city of Madison is the county seat. With FIPS code of 77, Jefferson County has a population of 33,141 and area of 361 square miles (935 km2).
List of all cities in Jefferson County, IN alphabetically
| City/Town | Postal Code | Area Code |
| Canaan, IN | 47224 | 812 |
| Deputy, IN | 47230 | 812 |
| Dupont, IN | 47231 | 812 |
| Hanover, IN | 47243 | 812 |
| Hanover Beach, IN | 47243 | 812 |
| Jefferson Proving Ground, IN | 47250 | 812 |
| Madison, IN | 47250 | 812 |
| North Madison, IN | 47250 | 812 |
| Paynesville, IN | 47243 | 812 |