Founded in 1843, Massac County is one of 102 counties in the state of Illinois. Historically, Massac County was formed from Pope and Johnson County. The city of Metropolis is the county seat. With FIPS code of 127, Massac County has a population of 13,960 and area of 237 square miles (614 km2).
List of all cities in Massac County, IL alphabetically
| City/Town | Postal Code | Area Code |
| Bargerville, IL | 62960 | 618/730 |
| Brookport, IL | 62910 | 618/730 |
| Hamletsburg, IL | 62910 | 618/730 |
| Joppa, IL | 62953 | 618/730 |
| Metropolis, IL | 62960 | 618/730 |
| New Liberty, IL | 62910 | 618/730 |
| Round Knob, IL | 62960 | 618/730 |
| Shady Grove, IL | 62910 | 618/730 |
| Unionville, IL | 62910 | 618/730 |