Founded in 1837, Cass County is one of 102 counties in the state of Illinois. Historically, Cass County was formed from Morgan County. The city of Virginia is the county seat. With FIPS code of 17, Cass County has a population of 12,773 and area of 375 square miles (971 km2).
List of all cities in Cass County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Arenzville, IL | 62611 | 217 |
| Ashland, IL | 62612 | 217 |
| Beardstown, IL | 62618 | 217 |
| Bluff Springs, IL | 62622 | 217 |
| Chandlerville, IL | 62627 | 217 |
| Little Indian, IL | 62691 | 217 |
| Newmansville, IL | 62612 | 217 |
| Panther Creek, IL | 62627 | 217 |
| Prentice, IL | 62612 | 217 |
| Virginia, IL | 62691 | 217 |
| Yatesville, IL | 62612 | 217 |