16 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Defiance | 1 | 17,041 | 17,045 | -0.01% | 1,333 | 13 | City |
| Defiance | 2 | 13,405 | 13,277 | 0.45% | 449 | 30 | Township |
| Noble | 3 | 6,028 | 5,955 | 0.47% | 258 | 23 | Township |
| Hicksville | 4 | 4,981 | 4,888 | 0.61% | 140 | 36 | Township |
| Hicksville | 5 | 3,417 | 3,429 | -0.06% | 1,338 | 3 | Village |
| Sherwood | 6 | 3,330 | 3,277 | -0.77% | 3,086 | 1 | CDP |
| Richland | 7 | 2,992 | 2,977 | 0.37% | 86 | 35 | Township |
| Washington | 8 | 1,550 | 1,537 | 0.45% | 43 | 36 | Township |
| Mark | 9 | 919 | 885 | 0.99% | 25 | 37 | Township |
| Farmer | 10 | 885 | 892 | 0.11% | 24 | 37 | Township |
| Adams | 11 | 884 | 878 | 0.45% | 25 | 36 | Township |
| Sherwood | 12 | 816 | 803 | 0.37% | 524 | 2 | Village |
| Brunersburg | 13 | 518 | 281 | 7.25% | 1,102 | 0 | CDP |
| Ney | 14 | 298 | 303 | -0.33% | 760 | 0 | Village |
| Florida | 15 | 210 | 217 | -0.47% | 933 | 0 | Village |
| Pulaski | 16 | 110 | 94 | -0.9% | 701 | 0 | CDP |
Defiance is the largest city in Defiance County, with a population of 17,041.
Pulaski is the smallest city in Defiance County, with a population of 110.
There are 16 cities in Defiance County, Ohio.