| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Maysville | 1 | 1,070 | 1,085 | -0.09% | 934 | 1 | City |
| Stewartsville | 2 | 721 | 737 | -0.28% | 730 | 1 | City |
| Union Star | 3 | 371 | 380 | -0.27% | 1,416 | 0 | Town |
| Osborn | 4 | 369 | 372 | 0% | 647 | 1 | City |
| Clarksdale | 5 | 243 | 248 | -0.41% | 750 | 0 | City |
| Weatherby | 6 | 76 | 78 | -1.3% | 644 | 0 | Town |
| Amity | 7 | 25 | 26 | 0% | 145 | 0 | Town |
Maysville is the largest city in DeKalb County, with a population of 1,070.
Amity is the smallest city in DeKalb County, with a population of 25.
There are 7 cities in DeKalb County, Missouri.