16 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Defiance | 1 | 17,212 | 17,050 | 0.19% | 1,346 | 13 | City |
| Defiance | 2 | 13,470 | 13,278 | 0.56% | 451 | 30 | Township |
| Noble | 3 | 6,051 | 5,955 | 0.51% | 259 | 23 | Township |
| Hicksville | 4 | 4,993 | 4,889 | 0.56% | 140 | 36 | Township |
| Hicksville | 5 | 3,452 | 3,427 | 0.15% | 1,352 | 3 | Village |
| Sherwood | 6 | 3,330 | 3,277 | -0.77% | 3,086 | 1 | CDP |
| Richland | 7 | 3,017 | 2,978 | 0.57% | 86 | 35 | Township |
| Washington | 8 | 1,555 | 1,535 | 0.52% | 43 | 36 | Township |
| Mark | 9 | 913 | 887 | 0.33% | 25 | 37 | Township |
| Farmer | 10 | 891 | 892 | 0.34% | 24 | 37 | Township |
| Adams | 11 | 886 | 878 | 0.57% | 25 | 36 | Township |
| Sherwood | 12 | 826 | 804 | 0.49% | 530 | 2 | Village |
| Brunersburg | 13 | 518 | 281 | 7.25% | 1,102 | 0 | CDP |
| Ney | 14 | 299 | 301 | -0.33% | 763 | 0 | Village |
| Florida | 15 | 214 | 221 | -0.93% | 951 | 0 | Village |
| Pulaski | 16 | 110 | 94 | -0.9% | 701 | 0 | CDP |
Defiance is the largest city in Defiance County, with a population of 17,212.
Pulaski is the smallest city in Defiance County, with a population of 110.
There are 16 cities in Defiance County, Ohio.