9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Montgomery City | 1 | 2,802 | 2,799 | 0.04% | 830 | 3 | City |
| Wellsville | 2 | 1,018 | 988 | 0.59% | 662 | 2 | City |
| Jonesburg | 3 | 803 | 723 | 2.03% | 468 | 2 | City |
| New Florence | 4 | 642 | 639 | 0.16% | 214 | 3 | City |
| Bellflower | 5 | 341 | 328 | 0.89% | 610 | 1 | City |
| High Hill | 6 | 182 | 182 | 0% | 396 | 0 | City |
| Middletown | 7 | 170 | 170 | 0% | 530 | 0 | Town |
| Rhineland | 8 | 138 | 140 | 0% | 409 | 0 | Town |
| Big Spring | 9 | 19 | 227 | -34.48% | 6 | 3 | CDP |
Montgomery City is the largest city in Montgomery County, with a population of 2,802.
Big Spring is the smallest city in Montgomery County, with a population of 19.
There are 9 cities in Montgomery County, Missouri.