27 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Benton | 1 | 19,037 | 18,926 | 0.37% | 1,345 | 14 | Township |
| Benton | 2 | 8,500 | 8,724 | -0.38% | 235 | 36 | Township |
| West Frankfort | 3 | 7,067 | 7,258 | -0.45% | 1,418 | 5 | City |
| Benton | 4 | 6,517 | 6,699 | -0.46% | 1,187 | 5 | City |
| Denning | 5 | 4,611 | 4,736 | -0.43% | 129 | 36 | Township |
| Tyrone | 6 | 4,552 | 4,690 | -0.44% | 129 | 35 | Township |
| Six Mile | 7 | 3,446 | 3,526 | -0.35% | 95 | 36 | Township |
| Logan | 8 | 3,248 | 3,243 | 0.5% | 89 | 37 | Township |
| Goode | 9 | 2,623 | 2,634 | 0.34% | 94 | 28 | Township |
| Christopher | 10 | 2,590 | 2,682 | -0.58% | 1,597 | 2 | City |
| McLeansboro | 11 | 2,564 | 2,651 | -0.54% | 934 | 3 | City |
| Sesser | 12 | 1,867 | 1,893 | -0.21% | 1,813 | 1 | City |
| Cave | 13 | 1,644 | 1,680 | -0.3% | 46 | 36 | Township |
| Zeigler | 14 | 1,457 | 1,481 | -0.27% | 1,072 | 1 | City |
| Ewing | 15 | 1,299 | 1,338 | -0.46% | 36 | 36 | Township |
| Royalton | 16 | 1,032 | 1,064 | -0.48% | 926 | 1 | Village |
| West City | 17 | 633 | 654 | -0.47% | 394 | 2 | Village |
| Eastern | 18 | 569 | 583 | -0.35% | 16 | 36 | Township |
| Valier | 19 | 531 | 554 | -0.75% | 472 | 1 | Village |
| Barren | 20 | 529 | 542 | -0.19% | 25 | 21 | Township |
| North City | 21 | 493 | 510 | -0.6% | 227 | 2 | Village |
| Thompsonville | 22 | 476 | 485 | -0.21% | 234 | 2 | Village |
| Northern | 23 | 443 | 455 | -0.23% | 12 | 36 | Township |
| Buckner | 24 | 393 | 407 | -0.51% | 451 | 1 | Village |
| Orient | 25 | 317 | 328 | -0.63% | 426 | 1 | City |
| Hanaford | 26 | 312 | 320 | -0.32% | 310 | 1 | Village |
| Ewing | 27 | 292 | 303 | -0.68% | 289 | 1 | Village |
Benton is the largest city in Franklin County, with a population of 19,037.
Ewing is the smallest city in Franklin County, with a population of 292.
There are 27 cities in Franklin County, Illinois.