10 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Manchester | 1 | 5,335 | 5,074 | 0.98% | 1,102 | 5 | City |
| Earlville | 2 | 712 | 716 | -0.14% | 1,292 | 1 | City |
| Hopkinton | 3 | 622 | 621 | 0% | 969 | 1 | City |
| Delhi | 4 | 443 | 416 | 1.14% | 467 | 1 | City |
| Colesburg | 5 | 377 | 385 | -0.53% | 1,282 | 0 | City |
| Ryan | 6 | 347 | 349 | -0.29% | 792 | 0 | City |
| Greeley | 7 | 216 | 216 | 0% | 576 | 0 | City |
| Dundee | 8 | 193 | 193 | 0% | 613 | 0 | City |
| Delaware | 9 | 138 | 140 | -0.72% | 189 | 1 | City |
| Masonville | 10 | 97 | 99 | -1.02% | 297 | 0 | City |
Manchester is the largest city in Delaware County, with a population of 5,335.
Masonville is the smallest city in Delaware County, with a population of 97.
There are 10 cities in Delaware County, Iowa.