Waterloo, IL Area Codes
Waterloo is served by area code 618. It is in Illinois, Monroe County. About 18,208 people live in its 1 ZIP codes.
| Field | Value |
|---|---|
| Area code(s) | 618 |
| State / province | Illinois |
| County | Monroe County |
| Population | 18,208 |
| ZIP codes | 1 |
| Time zone | Central |
| Coordinates | 38.3088, -90.1494 |
What area code is Waterloo in?
| Area code | Main state | Population covered | Overlap |
|---|---|---|---|
| 618 | Illinois | 1,184,182 | — |
ZIP codes in the code footprint
Nearby towns and their area codes
Columbia 618, 730Belleville 618, 730East Saint Louis 618, 730Fairview Heights 618, 730Mascoutah 618O Fallon 618, 730Collinsville 618, 730Granite City 618, 730
How to dial
Dial 618 + 7 digits for a number in Waterloo, or +1 618 ... from abroad. Ten-digit dialling is required everywhere in the North American Numbering Plan.