17 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Montgomery City | 1 | 2,789 | 2,812 | -0.11% | 826 | 3 | City |
| Montgomery City | 2 | 2,789 | 2,803 | -0.11% | 826 | 3 | City |
| Wellsville | 3 | 1,010 | 991 | 0.4% | 657 | 2 | City |
| Wellsville | 4 | 1,010 | 988 | 0.4% | 657 | 2 | City |
| Jonesburg | 5 | 836 | 725 | 2.7% | 487 | 2 | City |
| Jonesburg | 6 | 836 | 723 | 2.7% | 487 | 2 | City |
| New Florence | 7 | 635 | 639 | -0.16% | 211 | 3 | City |
| New Florence | 8 | 635 | 637 | -0.16% | 211 | 3 | City |
| Bellflower | 9 | 339 | 330 | 0.59% | 606 | 1 | City |
| Bellflower | 10 | 339 | 329 | 0.59% | 606 | 1 | City |
| High Hill | 11 | 184 | 187 | -0.54% | 400 | 0 | City |
| High Hill | 12 | 184 | 186 | -0.54% | 400 | 0 | City |
| Middletown | 13 | 170 | 171 | 0% | 530 | 0 | Town |
| Middletown | 14 | 170 | 170 | 0% | 530 | 0 | Town |
| Rhineland | 15 | 135 | 137 | -0.74% | 401 | 0 | Town |
| Rhineland | 16 | 135 | 137 | -0.74% | 401 | 0 | Town |
| Big Spring | 17 | 19 | 227 | -34.48% | 6 | 3 | CDP |
Montgomery City is the largest city in Montgomery County, with a population of 2,789.
Big Spring is the smallest city in Montgomery County, with a population of 19.
There are 17 cities in Montgomery County, Missouri.