- Located near the intersections of US 45, IL 13, and IL 34
southwest of Eldorado and east of Marion
- Latitude: 37°44'18" N (+37.7383)
- Longitude: 88°32'26" W (-88.5406)
- Elevation: 403 feet above sea level
- Civil township: Harrisburg
- Land area: 6.2 square miles
- Water area: 0.14 square miles (90.3 acres)
As the crow flies, Harrisburg is...
| Year | Population | Percent change |
|---|
| 1990 | 9,289 | -- |
| 2000 | 9,860 | +6.1% |