City | Rank | 2026 Pop.↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Breese | 1 | 4,589 | 4,659 | -0.28% | 1,717 | 3 | City |
| New Baden | 2 | 3,368 | 3,422 | -0.3% | 1,845 | 2 | Village |
| Carlyle | 3 | 3,177 | 3,243 | -0.35% | 928 | 3 | City |
| Trenton | 4 | 2,635 | 2,682 | -0.3% | 1,399 | 2 | City |
| Aviston | 5 | 2,473 | 2,353 | 0.77% | 1,546 | 2 | Village |
| Germantown | 6 | 1,391 | 1,329 | 0.87% | 1,364 | 1 | Village |
| Albers | 7 | 1,111 | 1,132 | -0.27% | 1,120 | 1 | Village |
| Wamac | 8 | 956 | 984 | -0.62% | 676 | 1 | City |
| Beckemeyer | 9 | 921 | 921 | 0% | 1,493 | 1 | Village |
| Bartelso | 10 | 646 | 633 | 0.31% | 983 | 1 | Village |
| Damiansville | 11 | 559 | 568 | -0.53% | 680 | 1 | Village |
| Junction City | 12 | 514 | 532 | -0.58% | 751 | 1 | Village |
| St. Rose | 13 | 472 | 464 | 0.21% | 799 | 1 | Village |
| Hoffman | 14 | 429 | 437 | -0.46% | 848 | 1 | Village |
| Keyesport | 15 | 403 | 408 | -0.25% | 560 | 1 | Village |
| Huey | 16 | 159 | 163 | -0.63% | 736 | 0 | Village |
Breese is the largest city in Clinton County, with a population of 4,589.
Huey is the smallest city in Clinton County, with a population of 159.
There are 16 cities in Clinton County, Illinois.