53 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Ottawa | 1 | 12,758 | 12,625 | 0.2% | 1,236 | 10 | City |
| Ottawa | 2 | 12,758 | 12,633 | 0.2% | 1,236 | 10 | City |
| Wellsville | 3 | 1,929 | 1,947 | -0.21% | 1,122 | 2 | City |
| Wellsville | 4 | 1,929 | 1,946 | -0.21% | 1,122 | 2 | City |
| Pomona | 5 | 1,133 | 1,121 | 0.09% | 55 | 21 | Township |
| Pomona | 6 | 1,133 | 1,125 | 0.09% | 55 | 21 | Township |
| Centropolis | 7 | 1,044 | 1,023 | 0.38% | 26 | 41 | Township |
| Centropolis | 8 | 1,044 | 1,025 | 0.38% | 26 | 41 | Township |
| Pomona | 9 | 892 | 883 | 0.11% | 945 | 1 | City |
| Pomona | 10 | 892 | 887 | 0.11% | 945 | 1 | City |
| Ottawa | 11 | 841 | 821 | 0.48% | 20 | 42 | Township |
| Ottawa | 12 | 841 | 823 | 0.48% | 20 | 42 | Township |
| Cutler | 13 | 816 | 793 | 0.62% | 19 | 43 | Township |
| Cutler | 14 | 816 | 795 | 0.62% | 19 | 43 | Township |
| Richmond | 15 | 806 | 814 | -0.37% | 23 | 35 | Township |
| Richmond | 16 | 806 | 814 | -0.37% | 23 | 35 | Township |
| Ohio | 17 | 761 | 745 | 0.13% | 18 | 42 | Township |
| Ohio | 18 | 761 | 745 | 0.13% | 18 | 42 | Township |
| Williamsburg | 19 | 703 | 703 | -0.28% | 13 | 56 | Township |
| Williamsburg | 20 | 703 | 703 | -0.28% | 13 | 56 | Township |
| Peoria | 21 | 676 | 656 | 0.45% | 19 | 35 | Township |
| Peoria | 22 | 676 | 655 | 0.45% | 19 | 35 | Township |
| Pottawatomie | 23 | 605 | 591 | 0.5% | 16 | 39 | Township |
| Pottawatomie | 24 | 605 | 591 | 0.5% | 16 | 39 | Township |
| Homewood | 25 | 555 | 544 | 0.36% | 18 | 30 | Township |
| Homewood | 26 | 555 | 543 | 0.36% | 18 | 30 | Township |
| Richmond | 27 | 480 | 498 | -0.41% | 14 | 34 | Township |
| Richmond | 28 | 480 | 497 | -0.41% | 14 | 34 | Township |
| Harrison | 29 | 453 | 442 | 0.44% | 18 | 25 | Township |
| Harrison | 30 | 453 | 442 | 0.44% | 18 | 25 | Township |
| Hayes | 31 | 443 | 433 | 0.68% | 15 | 30 | Township |
| Hayes | 32 | 443 | 433 | 0.68% | 15 | 30 | Township |
| Richmond | 33 | 436 | 448 | -0.68% | 1,279 | 0 | City |
| Richmond | 34 | 436 | 448 | -0.68% | 1,279 | 0 | City |
| Greenwood | 35 | 398 | 390 | 0.51% | 13 | 30 | Township |
| Greenwood | 36 | 398 | 390 | 0.51% | 13 | 30 | Township |
| Williamsburg | 37 | 384 | 389 | -0.26% | 393 | 1 | City |
| Williamsburg | 38 | 384 | 389 | -0.26% | 393 | 1 | City |
| Appanoose | 39 | 323 | 319 | 0% | 11 | 30 | Township |
| Appanoose | 40 | 323 | 319 | 0% | 11 | 30 | Township |
| Princeton | 41 | 252 | 247 | 0.4% | 648 | 0 | City |
| Princeton | 42 | 252 | 247 | 0.4% | 648 | 0 | City |
| Lane | 43 | 244 | 239 | 0.41% | 1,047 | 0 | City |
| Lane | 44 | 244 | 239 | 0.41% | 1,047 | 0 | City |
| Rantoul | 45 | 175 | 169 | 0.57% | 1,190 | 0 | City |
| Rantoul | 46 | 175 | 169 | 0.57% | 1,190 | 0 | City |
| Centropolis | 47 | 115 | 149 | 7.48% | 343 | 0 | CDP |
| Lane | 48 | 104 | 106 | 0% | 3 | 36 | Township |
| Lane | 49 | 104 | 106 | 0% | 3 | 36 | Township |
| Lane | 50 | 75 | 77 | -1.32% | 1 | 53 | Township |
| Lane | 51 | 75 | 77 | -1.32% | 1 | 53 | Township |
| Ottawa | 52 | 40 | 36 | 5.26% | 1 | 36 | Township |
| Ottawa | 53 | 40 | 36 | 5.26% | 1 | 36 | Township |
Ottawa is the largest city in Franklin County, with a population of 12,758.
Ottawa is the smallest city in Franklin County, with a population of 40.
There are 53 cities in Franklin County, Kansas.