28 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Chester | 1 | 6,745 | 6,828 | -0.21% | 1,169 | 6 | City |
| Chester | 2 | 6,745 | 6,812 | -0.21% | 1,169 | 6 | City |
| Sparta | 3 | 4,030 | 4,092 | -0.25% | 361 | 11 | City |
| Sparta | 4 | 4,030 | 4,080 | -0.25% | 361 | 11 | City |
| Red Bud | 5 | 3,755 | 3,801 | -0.21% | 1,432 | 3 | City |
| Red Bud | 6 | 3,755 | 3,792 | -0.21% | 1,432 | 3 | City |
| Steeleville | 7 | 1,889 | 1,925 | -0.32% | 1,240 | 2 | Village |
| Steeleville | 8 | 1,889 | 1,919 | -0.32% | 1,240 | 2 | Village |
| Sparta | 9 | 1,035 | 1,063 | 0.1% | 29 | 36 | Township |
| Sparta | 10 | 1,035 | 1,060 | 0.1% | 29 | 36 | Township |
| Percy | 11 | 906 | 911 | -0.11% | 924 | 1 | Village |
| Percy | 12 | 906 | 910 | -0.11% | 924 | 1 | Village |
| Coulterville | 13 | 825 | 831 | -0.12% | 1,450 | 1 | Village |
| Coulterville | 14 | 825 | 829 | -0.12% | 1,450 | 1 | Village |
| Tilden | 15 | 750 | 751 | 0% | 769 | 1 | Village |
| Tilden | 16 | 750 | 749 | 0% | 769 | 1 | Village |
| Chester | 17 | 648 | 654 | 0.15% | 17 | 38 | Township |
| Chester | 18 | 648 | 652 | 0.15% | 17 | 38 | Township |
| Evansville | 19 | 537 | 548 | -0.37% | 681 | 1 | Village |
| Evansville | 20 | 537 | 546 | -0.37% | 681 | 1 | Village |
| Ellis Grove | 21 | 328 | 328 | 0% | 668 | 0 | Village |
| Ellis Grove | 22 | 328 | 327 | 0% | 668 | 0 | Village |
| Baldwin | 23 | 314 | 319 | -0.32% | 471 | 1 | Village |
| Baldwin | 24 | 314 | 318 | -0.32% | 471 | 1 | Village |
| Rockwood | 25 | 30 | 32 | -3.23% | 142 | 0 | Village |
| Rockwood | 26 | 30 | 32 | -3.23% | 142 | 0 | Village |
| Kaskaskia | 27 | 23 | 23 | 0% | 217 | 0 | Village |
| Kaskaskia | 28 | 23 | 23 | 0% | 217 | 0 | Village |
Chester is the largest city in Randolph County, with a population of 6,745.
Kaskaskia is the smallest city in Randolph County, with a population of 23.
There are 28 cities in Randolph County, Illinois.