13 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Maysville | 1 | 1,095 | 1,090 | 0.09% | 955 | 1.15 | City |
| Stewartsville | 2 | 732 | 736 | -0.14% | 741 | 0.99 | City |
| Colfax township | 3 | 701 | 693 | 0% | 17 | 41.81 | Township |
| Adams township | 4 | 629 | 637 | -0.63% | 15 | 41.95 | Township |
| Grand River township | 5 | 506 | 4,976 | -73.14% | 14 | 35.62 | Township |
| Sherman township | 6 | 479 | 487 | -0.62% | 9 | 55.92 | Township |
| Osborn | 7 | 376 | 373 | 0.27% | 660 | 0.57 | City |
| Union Star | 8 | 376 | 380 | -0.27% | 1,435 | 0.26 | Town |
| Grant township | 9 | 339 | 340 | -0.59% | 7 | 49.83 | Township |
| Dallas township | 10 | 267 | 268 | -0.37% | 6 | 42.16 | Township |
| Clarksdale | 11 | 247 | 246 | 0% | 762 | 0.32 | City |
| Weatherby | 12 | 78 | 78 | 0% | 661 | 0.12 | Town |
| Amity | 13 | 26 | 26 | 0% | 150 | 0.17 | Town |
Maysville is the largest city in DeKalb County, with a population of 1,095.
Amity is the smallest city in DeKalb County.
There are 13 cities in DeKalb County, Missouri.