27 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Macomb | 1 | 14,647 | 15,000 | -0.4% | 1,351 | 11 | City |
| Macomb City | 2 | 14,465 | 15,000 | -1.03% | 1,364 | 11 | Township |
| Bushnell | 3 | 2,791 | 2,918 | -1.2% | 153 | 18 | Township |
| Bushnell | 4 | 2,620 | 2,706 | -0.53% | 1,238 | 2 | City |
| Colchester | 5 | 1,490 | 1,560 | -1.26% | 83 | 18 | Township |
| Emmet | 6 | 1,196 | 1,247 | -1.16% | 37 | 33 | Township |
| Colchester | 7 | 1,070 | 1,105 | -0.56% | 930 | 1 | City |
| Blandinsville | 8 | 722 | 759 | -1.37% | 19 | 37 | Township |
| Chalmers | 9 | 682 | 708 | -1.02% | 26 | 27 | Township |
| Industry | 10 | 558 | 587 | -1.41% | 15 | 37 | Township |
| Blandinsville | 11 | 544 | 562 | -0.55% | 622 | 1 | Village |
| Prairie City | 12 | 493 | 516 | -1.4% | 27 | 18 | Township |
| Lamoine | 13 | 489 | 492 | -0.61% | 13 | 37 | Township |
| Walnut Grove | 14 | 447 | 463 | -1.11% | 12 | 36 | Township |
| Sciota | 15 | 446 | 465 | -1.11% | 12 | 38 | Township |
| Macomb | 16 | 430 | 453 | -1.6% | 13 | 32 | Township |
| Prairie City | 17 | 395 | 407 | -0.5% | 392 | 1 | Village |
| Scotland | 18 | 393 | 409 | -1.01% | 11 | 36 | Township |
| Industry | 19 | 383 | 395 | -0.52% | 833 | 0 | Village |
| Good Hope | 20 | 349 | 360 | -0.57% | 1,163 | 0 | Village |
| Tennessee | 21 | 299 | 308 | -0.99% | 10 | 29 | Township |
| Bethel | 22 | 292 | 304 | -1.02% | 8 | 37 | Township |
| Mound | 23 | 235 | 245 | -1.26% | 6 | 36 | Township |
| Bardolph | 24 | 202 | 207 | -0.49% | 327 | 1 | Village |
| Hire | 25 | 196 | 203 | -1.01% | 5 | 38 | Township |
| Tennessee | 26 | 100 | 100 | 0% | 235 | 0 | Village |
| Sciota | 27 | 35 | 37 | 0% | 112 | 0 | Village |
Macomb is the largest city in McDonough County, with a population of 14,647.
Sciota is the smallest city in McDonough County, with a population of 35.
There are 27 cities in McDonough County, Illinois.