6 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Warrenton | 1 | 9,850 | 8,559 | 2.23% | 1,089 | 9 | City |
| Wright City | 2 | 6,159 | 4,850 | 3.67% | 1,016 | 6 | City |
| Marthasville | 3 | 1,323 | 1,260 | 0.84% | 1,549 | 1 | City |
| Truesdale | 4 | 958 | 870 | 1.59% | 748 | 1 | City |
| Pendleton | 5 | 37 | 34 | 2.78% | 121 | 0 | Village |
| Three Creeks | 6 | 8 | 8 | 0% | 2 | 5 | Village |
Warrenton is the largest city in Warren County, with a population of 9,850.
Three Creeks is the smallest city in Warren County, with a population of 8.
There are 6 cities in Warren County, Missouri.