- Location: Saline County, Illinois
- Legal status: City
- Population: 4,534 (Change since 1990: -0.0%)
- Name origin: Samuel Elder + Joseph Reed
- Previously known as: Elderedo
- Located at the intersection of US 45 and IL 142 northeast
of Harrisburg
- Latitude: 37°48'49" N (+37.8136)
- Longitude: 88°26'17" W (-88.4381)
- Elevation: 389 feet above sea level
- Civil township: East Eldorado
- Land area: 2.3 square miles
- Water area: 0.03 square miles (20.2 acres)
As the crow flies, Eldorado is...
| Year | Population | Percent change |
|---|
| 1990 | 4,536 | -- |
| 2000 | 4,534 | -0.0% |