| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Marysville | 1 | 3,376 | 3,442 | -0.27% | 740 | 5 | City |
| Blue Rapids | 2 | 906 | 928 | -0.33% | 456 | 2 | City |
| Frankfort | 3 | 716 | 725 | -0.28% | 711 | 1 | City |
| Waterville | 4 | 640 | 661 | -0.62% | 1,301 | 0 | City |
| Axtell | 5 | 406 | 397 | 0.25% | 776 | 1 | City |
| Beattie | 6 | 197 | 201 | -0.51% | 860 | 0 | City |
| Summerfield | 7 | 121 | 126 | -0.82% | 351 | 0 | City |
| Vermillion | 8 | 78 | 78 | -1.27% | 375 | 0 | City |
| Oketo | 9 | 61 | 63 | -1.61% | 592 | 0 | City |
Marysville is the largest city in Marshall County, with a population of 3,376.
Oketo is the smallest city in Marshall County, with a population of 61.
There are 9 cities in Marshall County, Kansas.