7 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Maysville | 1 | 1,087 | 1,090 | 0% | 949 | 1 | City |
| Stewartsville | 2 | 731 | 736 | -0.14% | 740 | 1 | City |
| Osborn | 3 | 376 | 373 | 0.27% | 660 | 1 | City |
| Union Star | 4 | 375 | 380 | -0.27% | 1,431 | 0 | Town |
| Clarksdale | 5 | 246 | 246 | 0% | 759 | 0 | City |
| Weatherby | 6 | 78 | 78 | 0% | 661 | 0 | Town |
| Amity | 7 | 26 | 26 | 0% | 150 | 0 | Town |
Maysville is the largest city in DeKalb County, with a population of 1,087.
Amity is the smallest city in DeKalb County, with a population of 26.
There are 7 cities in DeKalb County, Missouri.