28 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Macomb City | 1 | 14,775 | 14,981 | -0.25% | 1,394 | 10.60 | Township |
| Macomb | 2 | 14,761 | 14,981 | -0.3% | 1,392 | 10.60 | City |
| Bushnell | 3 | 2,856 | 2,918 | -0.45% | 156 | 18.29 | Township |
| Bushnell | 4 | 2,651 | 2,705 | -0.41% | 1,252 | 2.12 | City |
| Colchester | 5 | 1,527 | 1,559 | -0.39% | 85 | 18.06 | Township |
| Emmet | 6 | 1,221 | 1,245 | -0.41% | 38 | 32.52 | Township |
| Colchester | 7 | 1,080 | 1,104 | -0.46% | 939 | 1.15 | City |
| Blandinsville | 8 | 752 | 761 | 0% | 20 | 37.33 | Township |
| Chalmers | 9 | 700 | 709 | -0.14% | 26 | 26.57 | Township |
| Industry | 10 | 579 | 587 | -0.17% | 16 | 37.18 | Township |
| Blandinsville | 11 | 551 | 563 | -0.36% | 630 | 0.88 | Village |
| Prairie City | 12 | 504 | 515 | -0.59% | 28 | 17.95 | Township |
| Lamoine | 13 | 503 | 495 | 0.4% | 14 | 36.88 | Township |
| Walnut Grove | 14 | 461 | 464 | 0% | 13 | 36.27 | Township |
| Sciota | 15 | 456 | 466 | -0.44% | 12 | 37.67 | Township |
| Macomb | 16 | 443 | 455 | -0.67% | 14 | 32.48 | Township |
| Scotland | 17 | 401 | 409 | -0.25% | 11 | 35.52 | Township |
| Prairie City | 18 | 398 | 407 | -0.5% | 395 | 1.01 | Village |
| Industry | 19 | 386 | 395 | -0.52% | 839 | 0.46 | Village |
| Good Hope | 20 | 352 | 361 | -0.56% | 1,173 | 0.30 | Village |
| Tennessee | 21 | 302 | 307 | -0.33% | 11 | 28.68 | Township |
| Bethel | 22 | 294 | 304 | -1.01% | 8 | 36.64 | Township |
| Adair | 23 | 256 | 179 | 1.19% | 595 | 0.43 | CDP |
| Mound | 24 | 239 | 241 | 0% | 7 | 36.23 | Township |
| Bardolph | 25 | 204 | 208 | -0.49% | 331 | 0.62 | Village |
| Hire | 26 | 203 | 204 | 0% | 5 | 37.77 | Township |
| Tennessee | 27 | 97 | 99 | 0% | 228 | 0.42 | Village |
| Sciota | 28 | 37 | 37 | 0% | 119 | 0.31 | Village |
Macomb City is the largest city in McDonough County, with a population of 14,775.
Sciota is the smallest city in McDonough County, with a population of 37.
There are 28 cities in McDonough County, Illinois.