What is the area code(s) for illinois state? The area code(s) of illinois is 217, 224, 309, 312, 331, 618, 630, 708, 773, 779, 815, 847, Cities of illinois ChampaignAlgonquinBloomingtonWest ChicagoAddisonEast AltonBellwoodBelvidere Click here to find US Area Code List