Founded in 1819, Alexander County is one of 102 counties in the state of Illinois. Historically, Alexander County was formed from Union County. The city of Cairo is the county seat. With FIPS code of 3, Alexander County has a population of 5,030 and area of 236 square miles (611 km2).
List of all cities in Alexander County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Cache, IL | 62914 | 618/730 |
| Cairo, IL | 62914 | 618/730 |
| East Cape Girardeau, IL | 62957 | 618/730 |
| Elco, IL | 62988 | 618/730 |
| Fayville, IL | 62990 | 618/730 |
| Future City, IL | 62914 | 618/730 |
| Gale, IL | 62990 | 618/730 |
| Klondike, IL | 62914 | 618/730 |
| McClure, IL | 62957 | 618/730 |
| Miller City, IL | 62962 | 618/730 |
| Olive Branch, IL | 62969 | 618/730 |
| Tamms, IL | 62988 | 618/730 |
| 62993 | 618/730 | |
| Thebes, IL | 62990 | 618/730 |
| Unity, IL | 62993 | 618/730 |
| Urbandale, IL | 62914 | 618/730 |