| District of Illinois area codes: 331 | |
|---|---|
| Country | United States |
| State/Province | Illinois |
| Major City | Lemont |
| Time Zone | Central |
| Prefix | County | Primary City | Company |
|---|---|---|---|
| 331-200 | Cook | Bartlett, IL | T-mobile Usa |
| 331-201 | Dupage | Downers Grove, IL | Cellco Partnership DBA Verizon Wireless |
| 331-202 | Dupage | Elmhurst, IL | Sprint Spectrum L.p. |
| 331-203 | Kane | Aurora, IL | Sprint Spectrum L.p. |
| 331-204 | Cook | Bartlett, IL | Broadvox-clec |
| 331-205 | Kane | Aurora, IL | T-mobile Usa |
| 331-206 | Kane | Aurora, IL | Sprint Spectrum L.p. |
| 331-207 | Kendall | Yorkville, IL | Level 3 Communications |
| 331-208 | Kane | Aurora, IL | Sprint Spectrum L.p. |
| 331-209 | Dupage | Elmhurst, IL | Level 3 Communications |
| 331-210 | Kane | Saint Charles, IL | Peerless Network Of Illinois |
| 331-212 | Kane | Aurora, IL | Mci Worldcom Communications |
| 331-213 | Dupage | Naperville, IL | Cellco Partnership DBA Verizon Wireless |
| 331-214 | Dupage | Downers Grove, IL | Cellco Partnership DBA Verizon Wireless |
| 331-215 | Dupage | Naperville, IL | Cellco Partnership DBA Verizon Wireless |
| 331-216 | Kendall | Oswego, IL | New Cingular Wireless PCS |
| 331-218 | Dupage | Wheaton, IL | T-mobile Usa |
| 331-220 | Kane | Aurora, IL | Sprint Spectrum L.p. |
| 331-221 | Dupage | Elmhurst, IL | Ameritech Illinois |
| 331-222 | Kane | Saint Charles, IL | Cricket Communications |
There are 75 prefixes, In the code area, the major cities are Addison, IL;Aurora, IL;Bartlett, IL;Batavia, IL;Be. The major city is Lemont.