5 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Olney | 1 | 8,301 | 8,691 | -0.78% | 1,198 | 7 | City |
| Noble | 2 | 604 | 630 | -0.66% | 594 | 1 | Village |
| Parkersburg | 3 | 185 | 187 | 0% | 224 | 1 | Village |
| Claremont | 4 | 154 | 162 | -0.65% | 194 | 1 | Village |
| Calhoun | 5 | 151 | 159 | -0.66% | 166 | 1 | Village |
Olney is the largest city in Richland County, with a population of 8,301.
Calhoun is the smallest city in Richland County, with a population of 151.
There are 5 cities in Richland County, Illinois.