Founded in 1841, Richland County is one of 102 counties in the state of Illinois. Historically, Richland County was formed from Clay and Lawrence County. The city of Olney is the county seat. With FIPS code of 159, Richland County has a population of 15,796 and area of 360 square miles (932 km2).
List of all cities in Richland County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Berryville, IL | 62419 | 618/730 |
| Bonpas, IL | 62419 | 618/730 |
| Calhoun, IL | 62419 | 618/730 |
| Claremont, IL | 62421 | 618/730 |
| Dundas, IL | 62425 | 618/730 |
| German, IL | 62421 | 618/730 |
| Noble, IL | 62868 | 618/730 |
| Olney, IL | 62450 | 618/730 |
| Orchard Heights, IL | 62450 | 618/730 |
| Parkersburg, IL | 62452 | 618/730 |
| Wynoose, IL | 62868 | 618/730 |