| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Chatfield | 1 | 3,021 | 3,003 | 0.1% | 1,167 | 3 | City |
| Spring Valley | 2 | 2,428 | 2,454 | -0.12% | 821 | 3 | City |
| Rushford | 3 | 1,846 | 1,863 | -0.16% | 1,119 | 2 | City |
| Preston | 4 | 1,317 | 1,321 | -0.08% | 534 | 2 | City |
| Harmony | 5 | 1,024 | 1,049 | -0.39% | 918 | 1 | City |
| Rushford Village | 6 | 797 | 793 | 0.13% | 24 | 34 | City |
| Lanesboro | 7 | 709 | 726 | -0.42% | 468 | 2 | City |
| Mabel | 8 | 697 | 715 | -0.43% | 1,449 | 0 | City |
| Wykoff | 9 | 436 | 432 | -0.23% | 467 | 1 | City |
| Fountain | 10 | 399 | 406 | -0.25% | 401 | 1 | City |
| Canton | 11 | 313 | 311 | 0% | 304 | 1 | City |
| Peterson | 12 | 224 | 232 | -0.88% | 472 | 0 | City |
| Ostrander | 13 | 222 | 230 | -0.89% | 467 | 0 | City |
| Whalan | 14 | 69 | 66 | 0% | 160 | 0 | City |
Chatfield is the largest city in Fillmore County, with a population of 3,021.
Whalan is the smallest city in Fillmore County, with a population of 69.
There are 14 cities in Fillmore County, Minnesota.