| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hillsboro | 1 | 2,632 | 2,724 | -0.53% | 1,079 | 2 | City |
| Marion | 2 | 1,890 | 1,920 | -0.37% | 685 | 3 | City |
| Peabody | 3 | 903 | 937 | -0.66% | 713 | 1 | City |
| Goessel | 4 | 557 | 560 | -0.18% | 1,470 | 0 | City |
| Florence | 5 | 374 | 390 | -0.8% | 488 | 1 | City |
| Burns | 6 | 226 | 233 | -0.44% | 657 | 0 | City |
| Lincolnville | 7 | 168 | 169 | 0% | 747 | 0 | City |
| Lehigh | 8 | 159 | 158 | 0% | 494 | 0 | City |
| Tampa | 9 | 101 | 107 | -0.98% | 567 | 0 | City |
| Durham | 10 | 89 | 91 | -1.11% | 511 | 0 | City |
| Ramona | 11 | 79 | 78 | 0% | 271 | 0 | City |
| Lost Springs | 12 | 54 | 54 | 0% | 243 | 0 | City |
Hillsboro is the largest city in Marion County, with a population of 2,632.
Lost Springs is the smallest city in Marion County, with a population of 54.
There are 12 cities in Marion County, Kansas.