Founded in 1795, Randolph County is one of 102 counties in the state of Illinois. Historically, Randolph County was formed from St. Clair County. The city of Chester is the county seat. With FIPS code of 157, Randolph County has a population of 30,142 and area of 575 square miles (1,489 km2).
List of all cities in Randolph County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Baldwin, IL | 62217 | 618/730 |
| Bremen, IL | 62233 | 618/730 |
| Chester, IL | 62233 | 618/730 |
| Coulterville, IL | 62237 | 618/730 |
| Eden, IL | 62286 | 618/730 |
| Ellis Grove, IL | 62241 | 618/730 |
| Evansville, IL | 62242 | 618/730 |
| Glenn, IL | 62280 | 618/730 |
| Grigg, IL | 62278 | 618/730 |
| Houston, IL | 62286 | 618/730 |
| Menard, IL | 62259 | 618/730 |
| Modoc, IL | 62261 | 618/730 |
| Percy, IL | 62272 | 618/730 |
| Prairie du Rocher, IL | 62261 | 618/730 |
| 62277 | 618/730 | |
| Red Bud, IL | 62278 | 618/730 |
| Rockwood, IL | 62280 | 618/730 |
| Ruma, IL | 62278 | 618/730 |
| Schulines, IL | 62286 | 618/730 |
| Sparta, IL | 62286 | 618/730 |
| Steeleville, IL | 62288 | 618/730 |
| Swanwick, IL | 62237 | 618/730 |
| Tilden, IL | 62292 | 618/730 |
| Walsh, IL | 62297 | 618/730 |
| Welge, IL | 62288 | 618/730 |
| Wine Hill, IL | 62288 | 618/730 |
| Winkle, IL | 62237 | 618/730 |