The 331 area code is a telephone area code serving portions of Chicago's near and far western suburbs, including the majority of DuPage County, Illinois. To start a free reverse phone lookup, simply enter the full 10-digit number (including the 331 area code) below and access available caller information such as name, address, and more.
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Area code 331 covers a significant portion of the western suburbs of Chicago, Illinois. This includes areas within DuPage, Cook, Kane, and Will counties, as well as a small portion of Kendall County.
Area code 331 is an overlay to area code 630. Area code 630 was created in 1996. Area code 331 was introduced on October 7, 2007, overlaying area code 630. Ten-digit dialing is mandatory in this area.
Area code 331 is a General Purpose Code which was placed in service on January 1, 1947.
Our reverse phone lookup will analyze the three-digit prefix of any 331 area code phone number and will show which telecommunications company and rate center it was initially assigned to. This prefix code data may help to determine the U.S. carrier, Illinois geographic region, and local calling area associated with the phone number.
| Company | Number of Prefixes |
|---|---|
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 12 |
| NEW CINGULAR WIRELESS PCS, LLC - IL | 8 |
| T-MOBILE USA, INC. | 8 |
| SPRINT SPECTRUM, L.P. | 4 |
| BANDWIDTH.COM CLEC, LLC - IL | 3 |
| LEVEL 3 COMMUNICATIONS, LLC - IL | 2 |
| ILLINOIS BELL TEL CO | 1 |
| LOCAL ACCESS LLC - IL | 1 |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL | 1 |
| ONVOY, LLC | 1 |
| OVATION COMMUNICATIONS OF ILLINOIS, INC. | 1 |
| PEERLESS NETWORK OF ILLINOIS, LLC - IL | 1 |
| RCN TELECOM SERVICES OF ILLINIOS, INC. - IL | 1 |
| Rate Center | Number of Prefixes |
|---|---|
| NAPERVILLE | 12 |
| AURORA | 10 |
| ST CHARLES | 5 |
| DOWNERSGRV | 4 |
| ELMHURST | 3 |
| LEMONT | 3 |
| BARTLETT | 2 |
| BIG ROCK | 1 |
| SUGARGROVE | 1 |
| W CHICAGO | 1 |
| WHEATON | 1 |
| YORKVILLE | 1 |
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