24 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Jacksonville | 1 | 17,690 | 18,245 | -0.62% | 1,675 | 11 | City |
| South Jacksonville | 2 | 3,173 | 3,292 | -0.75% | 1,402 | 2 | Village |
| Franklin | 3 | 2,196 | 2,229 | -0.05% | 61 | 36 | Township |
| Concord | 4 | 1,405 | 1,456 | -0.78% | 39 | 36 | Township |
| Waverly | 5 | 1,137 | 1,186 | -0.87% | 1,097 | 1 | City |
| Meredosia | 6 | 788 | 817 | -0.76% | 912 | 1 | Village |
| Franklin | 7 | 585 | 610 | -0.85% | 706 | 1 | Village |
| Murrayville | 8 | 541 | 563 | -0.92% | 1,091 | 0 | Village |
| Woodson | 9 | 480 | 497 | -0.83% | 1,218 | 0 | Village |
| Chapin | 10 | 458 | 477 | -0.87% | 459 | 1 | Village |
| Concord | 11 | 369 | 375 | 0.82% | 9 | 40 | Township |
| Alexander | 12 | 340 | 159 | 7.26% | 346 | 1 | CDP |
| Concord | 13 | 284 | 292 | -0.35% | 8 | 37 | Township |
| Curran | 14 | 209 | 212 | -0.48% | 106 | 2 | Village |
| Concord | 15 | 151 | 156 | -0.66% | 606 | 0 | Village |
| Berlin | 16 | 141 | 143 | -0.7% | 158 | 1 | Village |
| Literberry | 17 | 121 | 78 | 7.08% | 149 | 1 | CDP |
| Glasgow | 18 | 106 | 111 | -0.93% | 105 | 1 | Village |
| Naples | 19 | 96 | 101 | -1.03% | 159 | 1 | Town |
| Lynnville | 20 | 91 | 95 | -1.09% | 1,182 | 0 | Village |
| Exeter | 21 | 83 | 87 | -1.19% | 120 | 1 | Village |
| Oxville | 22 | 29 | 18 | 7.41% | 853 | 0 | CDP |
| Riggston | 23 | 22 | 15 | 4.76% | 846 | 0 | CDP |
| Merritt | 24 | 21 | 26 | 5% | 538 | 0 | CDP |
Jacksonville is the largest city in Morgan County, with a population of 17,690.
Merritt is the smallest city in Morgan County, with a population of 21.
There are 24 cities in Morgan County, Illinois.