- Located north of Marion
- Latitude: 37°49'14" N (+37.8206)
- Longitude: 88°55'39" W (-88.9275)
- Elevation: 450 feet above sea level
- Civil township: Lake Creek
- Land area: 2.0 square miles
- Water area: 0.06 square miles (37.0 acres)
As the crow flies, Johnston City is...
| Year | Population | Percent change |
|---|
| 1990 | 3,706 | -- |
| 2000 | 3,557 | -4.0% |