15 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| West Frankfort | 1 | 7,067 | 7,258 | -0.45% | 1,418 | 5 | City |
| Benton | 2 | 6,517 | 6,699 | -0.46% | 1,187 | 5 | City |
| Christopher | 3 | 2,590 | 2,682 | -0.58% | 1,597 | 2 | City |
| McLeansboro | 4 | 2,564 | 2,651 | -0.54% | 934 | 3 | City |
| Sesser | 5 | 1,867 | 1,893 | -0.21% | 1,813 | 1 | City |
| Zeigler | 6 | 1,457 | 1,481 | -0.27% | 1,072 | 1 | City |
| Royalton | 7 | 1,032 | 1,064 | -0.48% | 926 | 1 | Village |
| West City | 8 | 633 | 654 | -0.47% | 394 | 2 | Village |
| Valier | 9 | 531 | 554 | -0.75% | 472 | 1 | Village |
| North City | 10 | 493 | 510 | -0.6% | 227 | 2 | Village |
| Thompsonville | 11 | 476 | 485 | -0.21% | 234 | 2 | Village |
| Buckner | 12 | 393 | 407 | -0.51% | 451 | 1 | Village |
| Orient | 13 | 317 | 328 | -0.63% | 426 | 1 | City |
| Hanaford | 14 | 312 | 320 | -0.32% | 310 | 1 | Village |
| Ewing | 15 | 292 | 303 | -0.68% | 289 | 1 | Village |
West Frankfort is the largest city in Franklin County, with a population of 7,067.
Ewing is the smallest city in Franklin County, with a population of 292.
There are 15 cities in Franklin County, Illinois.