Founded in 1818, Franklin County is one of 102 counties in the state of Illinois. Historically, Franklin County was formed from White County and Gallatin County. The city of Benton is the county seat. With FIPS code of 55, Franklin County has a population of 37,442 and area of 408 square miles (1,057 km2).
List of all cities in Franklin County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Akin, IL | 62805 | 618/730 |
| Barren, IL | 62812 | 618/730 |
| Benton, IL | 62812 | 618/730 |
| Buckner, IL | 62819 | 618/730 |
| Cave, IL | 62890 | 618/730 |
| Christopher, IL | 62822 | 618/730 |
| Cleburne, IL | 62865 | 618/730 |
| Coello, IL | 62825 | 618/730 |
| Corinth, IL | 62890 | 618/730 |
| Deering, IL | 62896 | 618/730 |
| Denning, IL | 62896 | 618/730 |
| Eastern, IL | 62812 | 618/730 |
| Ewing, IL | 62836 | 618/730 |
| Ezra, IL | 62896 | 618/730 |
| Frankfort Heights, IL | 62840 | 618/730 |
| Frisco, IL | 62836 | 618/730 |
| Goode, IL | 62884 | 618/730 |
| Hanaford, IL | 62856 | 618/730 |
| Logan, IL | 62856 | 618/730 |
| Mulkeytown, IL | 62865 | 618/730 |
| Orient, IL | 62874 | 618/730 |
| Parrish, IL | 62890 | 618/730 |
| Plumfield, IL | 62896 | 618/730 |
| Rend City, IL | 62812 | 618/730 |
| Royalton, IL | 62983 | 618/730 |
| Sesser, IL | 62884 | 618/730 |
| Six Mile, IL | 62999 | 618/730 |
| Steel City, IL | 62812 | 618/730 |
| Stiritz, IL | 62896 | 618/730 |
| Thompsonville, IL | 62890 | 618/730 |
| Urbain, IL | 62865 | 618/730 |
| Valier, IL | 62891 | 618/730 |
| West City, IL | 62812 | 618/730 |
| West End, IL | 62890 | 618/730 |
| West Frankfort, IL | 62896 | 618/730 |
| Whittington, IL | 62897 | 618/730 |
| Zeigler, IL | 62999 | 618/730 |