33 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Decatur | 1 | 68,209 | 70,978 | -0.81% | 1,569 | 43 | City |
| Decatur | 2 | 45,948 | 47,517 | -0.11% | 1,581 | 29 | Township |
| Hickory Point | 3 | 17,717 | 18,195 | 0.03% | 498 | 36 | Township |
| Long Creek | 4 | 10,259 | 10,559 | 0.04% | 268 | 38 | Township |
| Mount Zion | 5 | 7,053 | 7,190 | 0.16% | 106 | 67 | Township |
| Mount Zion | 6 | 5,867 | 6,015 | -0.51% | 1,375 | 4 | Village |
| Whitmore | 7 | 4,190 | 4,305 | 0.05% | 117 | 36 | Township |
| South Wheatland | 8 | 3,918 | 4,025 | 0.1% | 141 | 28 | Township |
| Forsyth | 9 | 3,637 | 3,732 | -0.52% | 1,175 | 3 | Village |
| Maroa | 10 | 1,806 | 1,853 | 0.17% | 43 | 42 | Township |
| Harristown | 11 | 1,709 | 1,758 | 0.12% | 61 | 28 | Township |
| Maroa | 12 | 1,522 | 1,576 | -0.72% | 863 | 2 | City |
| South Macon | 13 | 1,420 | 1,461 | 0.21% | 42 | 34 | Township |
| Pleasant View | 14 | 1,368 | 1,417 | -0.15% | 45 | 31 | Township |
| Friends Creek | 15 | 1,328 | 1,371 | 0% | 27 | 49 | Township |
| Illini | 16 | 1,301 | 1,335 | -0.08% | 35 | 37 | Township |
| Harristown | 17 | 1,259 | 1,312 | -0.87% | 701 | 2 | Village |
| Long Creek | 18 | 1,224 | 1,261 | -0.65% | 434 | 3 | Village |
| Macon | 19 | 1,124 | 1,169 | -0.79% | 887 | 1 | City |
| Blue Mound | 20 | 1,080 | 1,130 | -0.92% | 1,846 | 1 | Village |
| Warrensburg | 21 | 1,079 | 1,112 | -0.64% | 1,482 | 1 | Village |
| Oakley | 22 | 956 | 981 | 0.21% | 33 | 29 | Township |
| Argenta | 23 | 872 | 911 | -0.91% | 1,335 | 1 | Village |
| Oreana | 24 | 850 | 888 | -0.93% | 1,816 | 0 | Village |
| Blue Mound | 25 | 794 | 812 | 0.13% | 24 | 33 | Township |
| Niantic | 26 | 727 | 752 | 0% | 25 | 29 | Township |
| Niantic | 27 | 582 | 609 | -1.02% | 560 | 1 | Village |
| Boody | 28 | 445 | 442 | 2.53% | 387 | 1 | CDP |
| Blue Mound | 29 | 387 | 388 | 0.26% | 10 | 38 | Township |
| Austin | 30 | 226 | 233 | 0% | 6 | 37 | Township |
| Macon | 31 | 199 | 205 | -0.5% | 5 | 37 | Township |
| Elwin | 32 | 80 | 143 | 6.67% | 96 | 1 | CDP |
| Lake City | 33 | 49 | 107 | 6.52% | 127 | 0 | CDP |
Decatur is the largest city in Macon County, with a population of 68,209.
Lake City is the smallest city in Macon County, with a population of 49.
There are 33 cities in Macon County, Illinois.