Monmouth, IL Area Codes
Monmouth is served by area code 309. It is in Illinois, Warren County. About 10,458 people live in its 1 ZIP codes.
| Field | Value |
|---|---|
| Area code(s) | 309 |
| State / province | Illinois |
| County | Warren County |
| Population | 10,458 |
| ZIP codes | 1 |
| Time zone | Central |
| Coordinates | 40.9099, -90.6517 |
What area code is Monmouth in?
| Area code | Main state | Population covered | Overlap |
|---|---|---|---|
| 309 | Illinois | 887,272 | — |
ZIP codes in the code footprint
Nearby towns and their area codes
Galesburg 309Macomb 309Milan 309, 861Moline 309, 861Canton 309Rock Island 309, 861Kewanee 309East Moline 309
How to dial
Dial 309 + 7 digits for a number in Monmouth, or +1 309 ... from abroad. Ten-digit dialling is required everywhere in the North American Numbering Plan.