15 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Decatur | 1 | 67,165 | 70,927 | -1.11% | 1,545 | 43.48 | City |
| Mount Zion | 2 | 5,787 | 6,014 | -0.77% | 1,356 | 4.27 | Village |
| Forsyth | 3 | 3,579 | 3,728 | -0.83% | 1,156 | 3.10 | Village |
| Maroa | 4 | 1,499 | 1,576 | -0.99% | 850 | 1.76 | City |
| Harristown | 5 | 1,237 | 1,309 | -1.12% | 688 | 1.80 | Village |
| Long Creek | 6 | 1,196 | 1,253 | -0.91% | 424 | 2.82 | Village |
| Macon | 7 | 1,102 | 1,171 | -1.25% | 870 | 1.27 | City |
| Warrensburg | 8 | 1,066 | 1,111 | -0.84% | 1,464 | 0.73 | Village |
| Blue Mound | 9 | 1,062 | 1,129 | -1.21% | 1,815 | 0.58 | Village |
| Argenta | 10 | 858 | 910 | -1.15% | 1,314 | 0.65 | Village |
| Oreana | 11 | 837 | 887 | -1.18% | 1,788 | 0.47 | Village |
| Niantic | 12 | 575 | 609 | -1.2% | 553 | 1.04 | Village |
| Boody | 13 | 445 | 442 | 2.54% | 387 | 1.15 | CDP |
| Elwin | 14 | 80 | 143 | 6.67% | 96 | 0.83 | CDP |
| Lake City | 15 | 49 | 107 | 6.52% | 127 | 0.39 | CDP |
Decatur is the largest city in Macon County, with a population of 67,165.
Lake City is the smallest city in Macon County.
There are 15 cities in Macon County, Illinois.