18 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Tuscola | 1 | 5,536 | 5,455 | 0.54% | 89 | 63 | Township |
| Tuscola | 2 | 4,664 | 4,646 | 0.06% | 1,582 | 3 | City |
| Bourbon | 3 | 4,226 | 4,096 | 0.76% | 98 | 43 | Township |
| Camargo | 4 | 3,501 | 3,515 | 0.17% | 91 | 39 | Township |
| Arcola | 5 | 3,287 | 3,281 | 0.31% | 61 | 54 | Township |
| Arcola | 6 | 2,907 | 2,931 | -0.14% | 1,437 | 2 | City |
| Villa Grove | 7 | 2,434 | 2,482 | -0.33% | 1,621 | 2 | City |
| Arthur | 8 | 2,289 | 2,229 | 0.44% | 1,712 | 1 | Village |
| Garrett | 9 | 1,334 | 1,320 | 0.53% | 26 | 52 | Township |
| Atwood | 10 | 1,087 | 1,116 | -0.46% | 1,770 | 1 | Village |
| Newman | 11 | 1,006 | 1,007 | 0.1% | 25 | 41 | Township |
| Newman | 12 | 770 | 779 | -0.13% | 1,256 | 1 | City |
| Bowdre | 13 | 632 | 626 | 0.48% | 13 | 48 | Township |
| Camargo | 14 | 452 | 452 | 0% | 359 | 1 | Village |
| Hindsboro | 15 | 271 | 277 | -0.37% | 1,007 | 0 | Village |
| Sargent | 16 | 255 | 249 | 0.79% | 5 | 47 | Township |
| Murdock | 17 | 229 | 231 | 0% | 7 | 31 | Township |
| Garrett | 18 | 129 | 128 | 0% | 1,194 | 0 | Village |
Tuscola is the largest city in Douglas County, with a population of 5,536.
Garrett is the smallest city in Douglas County, with a population of 129.
There are 18 cities in Douglas County, Illinois.