10 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Manchester | 1 | 5,387 | 5,074 | 0.97% | 1,113 | 5 | City |
| Earlville | 2 | 711 | 716 | -0.14% | 1,290 | 1 | City |
| Hopkinton | 3 | 622 | 621 | 0% | 969 | 1 | City |
| Delhi | 4 | 449 | 416 | 1.35% | 474 | 1 | City |
| Colesburg | 5 | 376 | 385 | -0.27% | 1,279 | 0 | City |
| Ryan | 6 | 347 | 349 | 0% | 792 | 0 | City |
| Greeley | 7 | 216 | 216 | 0% | 576 | 0 | City |
| Dundee | 8 | 193 | 193 | 0% | 613 | 0 | City |
| Delaware | 9 | 138 | 140 | 0% | 189 | 1 | City |
| Masonville | 10 | 97 | 99 | 0% | 297 | 0 | City |
Manchester is the largest city in Delaware County, with a population of 5,387.
Masonville is the smallest city in Delaware County, with a population of 97.
There are 10 cities in Delaware County, Iowa.