13 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Delaware | 1 | 47,455 | 41,712 | 2.48% | 2,345 | 20.24 | City |
| Westerville | 2 | 37,100 | 39,244 | -1.14% | 2,944 | 12.60 | City |
| Powell | 3 | 14,651 | 14,250 | 0.55% | 2,520 | 5.82 | City |
| Sunbury | 4 | 9,422 | 6,717 | 6.09% | 1,957 | 4.81 | Village |
| Huber Ridge | 5 | 4,226 | 4,213 | -0.61% | 4,036 | 1.05 | CDP |
| New California | 6 | 2,034 | 1,330 | 2.11% | 988 | 2.06 | CDP |
| Minerva Park | 7 | 1,900 | 2,010 | -1.15% | 2,937 | 0.65 | Village |
| Ashley | 8 | 1,392 | 1,207 | 2.73% | 2,112 | 0.66 | Village |
| Ostrander | 9 | 1,262 | 1,099 | 2.69% | 1,345 | 0.94 | Village |
| Galena | 10 | 1,074 | 934 | 2.68% | 621 | 1.73 | Village |
| Shawnee Hills | 11 | 965 | 840 | 2.66% | 2,169 | 0.45 | Village |
| Hartford (Croton) | 12 | 406 | 401 | 0.25% | 760 | 0.53 | Village |
| Radnor | 13 | 158 | 131 | -1.86% | 219 | 0.72 | CDP |
Delaware is the largest city in Delaware County, with a population of 47,455.
Radnor is the smallest city in Delaware County.
There are 13 cities in Delaware County, Ohio.