10 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Delaware | 1 | 48,925 | 41,712 | 2.52% | 2,397 | 20 | City |
| Westerville | 2 | 38,298 | 39,240 | -0.41% | 3,039 | 13 | City |
| Powell | 3 | 14,794 | 14,250 | 0.62% | 2,544 | 6 | City |
| Sunbury | 4 | 11,195 | 6,725 | 7.13% | 1,567 | 7 | City |
| Minerva Park | 5 | 1,936 | 2,010 | -0.62% | 2,992 | 1 | Village |
| Ashley | 6 | 1,421 | 1,207 | 2.6% | 2,156 | 1 | Village |
| Ostrander | 7 | 1,291 | 1,098 | 2.54% | 1,376 | 1 | Village |
| Galena | 8 | 1,068 | 926 | 2.3% | 618 | 2 | Village |
| Shawnee Hills | 9 | 988 | 841 | 2.6% | 2,220 | 0 | Village |
| Hartford (Croton) | 10 | 416 | 407 | 0.48% | 779 | 1 | Village |
Delaware is the largest city in Delaware County, with a population of 48,925.
Hartford (Croton) is the smallest city in Delaware County, with a population of 416.
There are 10 cities in Delaware County, Ohio.