28 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Macomb | 1 | 14,706 | 15,000 | -0.4% | 1,387 | 11 | City |
| Macomb City | 2 | 14,615 | 15,000 | -1.02% | 1,379 | 11 | Township |
| Bushnell | 3 | 2,825 | 2,918 | -1.19% | 154 | 18 | Township |
| Bushnell | 4 | 2,634 | 2,706 | -0.57% | 1,244 | 2 | City |
| Colchester | 5 | 1,509 | 1,560 | -1.24% | 84 | 18 | Township |
| Emmet | 6 | 1,210 | 1,247 | -1.14% | 37 | 33 | Township |
| Colchester | 7 | 1,076 | 1,105 | -0.55% | 936 | 1 | City |
| Blandinsville | 8 | 732 | 759 | -1.35% | 20 | 37 | Township |
| Chalmers | 9 | 689 | 708 | -1.01% | 26 | 27 | Township |
| Industry | 10 | 566 | 587 | -1.39% | 15 | 37 | Township |
| Blandinsville | 11 | 547 | 562 | -0.55% | 625 | 1 | Village |
| Prairie City | 12 | 500 | 516 | -1.38% | 28 | 18 | Township |
| Lamoine | 13 | 492 | 492 | -0.61% | 13 | 37 | Township |
| Walnut Grove | 14 | 452 | 463 | -1.09% | 12 | 36 | Township |
| Sciota | 15 | 451 | 465 | -1.1% | 12 | 38 | Township |
| Macomb | 16 | 437 | 453 | -1.58% | 13 | 32 | Township |
| Prairie City | 17 | 397 | 407 | -0.5% | 394 | 1 | Village |
| Scotland | 18 | 397 | 409 | -1% | 11 | 36 | Township |
| Industry | 19 | 385 | 395 | -0.52% | 837 | 0 | Village |
| Good Hope | 20 | 351 | 360 | -0.57% | 1,170 | 0 | Village |
| Tennessee | 21 | 302 | 308 | -0.98% | 11 | 29 | Township |
| Bethel | 22 | 295 | 304 | -1.01% | 8 | 37 | Township |
| Adair | 23 | 256 | 179 | 1.19% | 595 | 0 | CDP |
| Mound | 24 | 238 | 245 | -1.24% | 7 | 36 | Township |
| Bardolph | 25 | 203 | 207 | -0.49% | 329 | 1 | Village |
| Hire | 26 | 198 | 203 | -1% | 5 | 38 | Township |
| Tennessee | 27 | 100 | 100 | 0% | 235 | 0 | Village |
| Sciota | 28 | 35 | 37 | -2.78% | 112 | 0 | Village |
Macomb is the largest city in McDonough County, with a population of 14,706.
Sciota is the smallest city in McDonough County, with a population of 35.
There are 28 cities in McDonough County, Illinois.