Area code 309 is an area code that covers the Western part of central Illinois.
Illinois has area codes of 217, 224, 309, 312, 331, 447, 464, 618, 630, 708, 730, 773, 779, 815, 847, 872.
The following map shows the coverage of 309 area code. The coverage area is shown in green.
Area code map of the entire U.S.