| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Warrenton | 1 | 9,884 | 8,536 | 2.24% | 1,093 | 9 | City |
| Wright City | 2 | 6,073 | 4,867 | 3.74% | 1,002 | 6 | City |
| Marthasville | 3 | 1,313 | 1,265 | 0.84% | 1,537 | 1 | City |
| Truesdale | 4 | 1,069 | 868 | 1.42% | 835 | 1 | City |
| Pendleton | 5 | 30 | 29 | 0% | 98 | 0 | Village |
| Three Creeks | 6 | 6 | 6 | 0% | 1.0 | 5 | Village |
Warrenton is the largest city in Warren County, with a population of 9,884.
Three Creeks is the smallest city in Warren County, with a population of 6.
There are 6 cities in Warren County, Missouri.