| Place Name | Johnston City |
| Place Type | City |
| ZIP Code(s) | 62951 |
| County | Williamson County |
| Area Code(s) | 618 |
| Timezone | Central Daylight Time (CDT) |
| Population (2022) | 3,557 |
| Population Growth Rate (2010-19) | -4.49% |
| Majority Ethnicity | White 99.49% |
| Metro/Micro Stats Area | Carbondale-Marion, IL |
| US Congressional District(s) | Illinois 12th |
| State House Districts | 117 |
| State Senate Districts | 59 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 99.49% |
| African American | 0% |
| Hispanic | 0% |
| Asian | 0% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 0.51% |