Illinois, United States
Central Time
12:23 AM
Area Code
331
State / Province
Illinois
Country
United States
Time Zone
Central Time
Area code 331 covers 22 cities and communities across Illinois, based on telephone company rate center data.
Use the E.164 format for clickable phone links (RFC 3966):
<a href="tel:+13315550100">+13315550100</a><a href="tel:+13315550199">+13315550199</a>Look up which exchange in Illinois a specific 331 number is homed to, and whether its block is wireline or wireless. See what a reverse lookup can establish before relying on the answer.
224 active prefixes in this area code, assigned as 2,314 thousands-blocks — pooling splits one prefix across several carriers, so each block is listed separately with the rate centre it is homed to, its carrier of record, and the switch that serves it.
Showing blocks 1–100 of 2,314
| NPA-NXX | Block | Rate centre | Type | Carrier (OCN) | Switch | LATA | LIR | Dates |
|---|---|---|---|---|---|---|---|---|
| 331-200 | 0 | Bartlett | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-200 | 1 | Bartlett | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-200 | 2 | Bartlett | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 331-200 | 3 | Bartlett | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-200 | 4 | Bartlett | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-200 | 5 | Bartlett | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-200 | 6 | Bartlett | Landline or VoIP | CENTURYLINK COMMUNICATIONS, LLC (508J) | CHCGILDT8MD | 358 | — | — |
| 331-200 | 7 | Bartlett | Landline or VoIP | PEERLESS NETWORK OF ILLINOIS, LLC - IL (063E) | CHICAGO | 358 | — | — |
| 331-200 | 8 | Bartlett | Landline or VoIP | PEERLESS NETWORK OF ILLINOIS, LLC - IL (063E) | CHICAGO | 358 | — | — |
| 331-200 | 9 | Bartlett | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-200 | A | Bartlett | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-201 | 0 | Downers Grove | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-201 | 1 | Downers Grove | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-201 | 2 | Downers Grove | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-201 | 3 | Downers Grove | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-201 | 4 | Downers Grove | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-201 | 5 | Downers Grove | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-201 | 6 | Downers Grove | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 331-201 | 7 | Downers Grove | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 331-201 | 8 | Downers Grove | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | BURGILAHGT3 | 358 | — | — |
| 331-201 | 9 | Downers Grove | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-201 | A | Downers Grove | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-202 | 0 | Elmhurst | Landline or VoIP | ONVOY, LLC (224C) | — | 358 | — | — |
| 331-202 | 1 | Elmhurst | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-202 | 2 | Elmhurst | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-202 | 3 | Elmhurst | Landline or VoIP | ONVOY, LLC (224C) | — | 358 | — | — |
| 331-202 | 4 | Elmhurst | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-202 | 5 | Elmhurst | Landline or VoIP | TERRA NOVA TELECOM INC. (145J) | — | 358 | — | — |
| 331-202 | 6 | Elmhurst | Landline or VoIP | TERRA NOVA TELECOM INC. (145J) | — | 358 | — | — |
| 331-202 | 7 | Elmhurst | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-202 | 8 | Elmhurst | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-202 | A | Elmhurst | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 0 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 1 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 2 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 3 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 4 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 5 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 6 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 7 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 8 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-203 | 9 | Aurora | Wireless | ONVOY SPECTRUM, LLC (624H) | CHCGILIDXDX | 358 | — | — |
| 331-203 | A | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-204 | 0 | Naperville | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-204 | 1 | Naperville | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-204 | 2 | Naperville | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | SCBGILRRGT1 | 358 | — | — |
| 331-204 | 3 | Naperville | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-204 | 4 | Naperville | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-204 | 5 | Naperville | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-204 | 6 | Naperville | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | CHCGILNEXJX | 358 | — | — |
| 331-204 | 7 | Naperville | Landline or VoIP | TELNYX LLC (073H) | CHCGILWUJMD | 358 | — | — |
| 331-204 | 8 | Naperville | Landline or VoIP | IP HORIZON LLC (515J) | — | 358 | — | — |
| 331-204 | 9 | Naperville | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-204 | A | Naperville | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-205 | 0 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-205 | 1 | Aurora | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-205 | 2 | Aurora | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-205 | 3 | Aurora | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | — | 358 | — | — |
| 331-205 | 4 | Aurora | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | — | 358 | — | — |
| 331-205 | 5 | Aurora | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | — | 358 | — | — |
| 331-205 | 6 | Aurora | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | — | 358 | — | — |
| 331-205 | 7 | Aurora | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-205 | 8 | Aurora | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-205 | 9 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-205 | A | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-206 | 0 | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-206 | 1 | Aurora | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-206 | 9 | Aurora | Wireless | NEW CINGULAR WIRELESS PCS, LLC - IL (6534) | WCHCILBFGT0 | 358 | — | — |
| 331-206 | A | Aurora | Wireless | T-MOBILE USA, INC. (6529) | ELGNILOTGT5 | 358 | — | — |
| 331-207 | 0 | Yorkville | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-207 | 1 | Yorkville | Landline or VoIP | PEERLESS NETWORK OF ILLINOIS, LLC - IL (063E) | CHICAGO | 358 | — | — |
| 331-207 | 2 | Yorkville | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 331-207 | 3 | Yorkville | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-207 | 4 | Yorkville | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-207 | 5 | Yorkville | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-207 | 6 | Yorkville | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
| 331-207 | 7 | Yorkville | Landline or VoIP | CENTURYLINK COMMUNICATIONS, LLC (508J) | CHCGILDT8MD | 358 | — | — |
| 331-207 | 8 | Yorkville | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | CHCGILNEXJX | 358 | — | — |
| 331-207 | 9 | Yorkville | Landline or VoIP | PEERLESS NETWORK OF ILLINOIS, LLC - IL (063E) | CHICAGO | 358 | — | — |
| 331-207 | A | Yorkville | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 331-208 | 3 | Aurora | Landline or VoIP | TERRA NOVA TELECOM INC. (145J) | CHCGILWUSMD | 358 | — | — |
| 331-208 | 4 | Aurora | Landline or VoIP | TERRA NOVA TELECOM INC. (145J) | — | 358 | — | — |
| 331-208 | 5 | Aurora | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 331-208 | 6 | Aurora | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL (7196) | ELK GROVE VILLAGE | 358 | — | — |
| 331-208 | 7 | Aurora | Landline or VoIP | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - IL (7196) | ELK GROVE VILLAGE | 358 | — | — |
| 331-208 | 8 | Aurora | Wireless | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL (6333) | RVDLILBDAMD | 358 | — | — |
| 331-208 | 9 | Aurora | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 331-208 | A | Aurora | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | — | 358 | — | — |
| 331-209 | 0 | Elmhurst | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-209 | 1 | Elmhurst | Landline or VoIP | IP HORIZON LLC (515J) | — | 358 | — | — |
| 331-209 | 2 | Elmhurst | Landline or VoIP | ACCESS ONE, INC. - IL (5447) | CHCGILDTKMD | 358 | — | — |
| 331-209 | 3 | Elmhurst | Landline or VoIP | CLEAR RATE COMMUNICATIONS, LLC (046L) | — | 358 | — | — |
| 331-209 | 4 | Elmhurst | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-209 | 5 | Elmhurst | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-209 | 6 | Elmhurst | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 331-209 | 7 | Elmhurst | Landline or VoIP | CENTURYLINK COMMUNICATIONS, LLC (508J) | CHCGILDT8MD | 358 | — | — |
| 331-209 | 8 | Elmhurst | Landline or VoIP | BANDWIDTH.COM CLEC, LLC - IL (984E) | CHCGILWBXDZ | 358 | — | — |
| 331-209 | 9 | Elmhurst | Landline or VoIP | COMCAST IP PHONE, LLC (318J) | CHCGILNEXJX | 358 | — | — |
| 331-209 | A | Elmhurst | Landline or VoIP | LEVEL 3 COMMUNICATIONS, LLC - IL (6115) | CHICAGO | 358 | — | — |
| 331-210 | 0 | Geneva | Landline or VoIP | ONVOY, LLC (224C) | CHICAGO | 358 | — | — |
Block-level assignments from the North American Numbering Plan administrator, via localcallingguide.com.
Assigned Prefixes
224
Assignment Blocks
2,314
Rate Centers
22
Carriers of Record
34
| Type | Blocks | Share |
|---|---|---|
| Landline | 29 | 1% |
| Landline or VoIP | 1,266 | 55% |
| Wireless | 1,019 | 44% |
| Carrier | Blocks |
|---|---|
| ONVOY, LLC | 530 |
| T-MOBILE USA, INC. | 323 |
| NEW CINGULAR WIRELESS PCS, LLC - IL | 311 |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL | 294 |
| BANDWIDTH.COM CLEC, LLC - IL | 173 |
| ONVOY SPECTRUM, LLC | 75 |
| PEERLESS NETWORK OF ILLINOIS, LLC - IL | 66 |
| COMCAST IP PHONE, LLC | 65 |
| LEVEL 3 COMMUNICATIONS, LLC - IL | 49 |
| COMMIO, LLC | 47 |
| 24 other carriers | 381 |
Carrier of record for each block. Numbers ported to another carrier keep their original block assignment, so this is not a lookup of who serves a given number today.
| Rate Center | Prefixes | Blocks |
|---|---|---|
| Aurora | 45 | 482 |
| Naperville | 33 | 353 |
| Geneva | 27 | 268 |
| Downers Grove | 21 | 231 |
| Lombard | 13 | 141 |
| Elmhurst | 10 | 105 |
| Lemont | 10 | 102 |
| Bartlett | 8 | 80 |
| West Chicago | 8 | 77 |
| Wheaton | 8 | 80 |
| Oswego | 7 | 71 |
| Hinsdale | 6 | 66 |
| Sugar Grove | 6 | 60 |
| Yorkville | 4 | 37 |
| Bensenville | 3 | 24 |
| Elburn | 3 | 31 |
| Glen Ellyn | 3 | 25 |
| Big Rock | 2 | 17 |
| Kaneville | 2 | 13 |
| Plano | 2 | 22 |
| Warrenville | 2 | 18 |
| Roselle | 1 | 11 |
A rate center is the telephone exchange area a number is homed to. It sets local calling boundaries, and is not the caller's current location.
Area code 331 is a North American Numbering Plan (NANP) telephone area code assigned to Illinois, United States. It is one of 17 area codes serving Illinois. As population and demand for phone numbers grew, the region was divided into multiple numbering plan areas to avoid exhausting the available 7-digit number pool.
Yes. 331 is an active North American Numbering Plan (NANP) area code, currently assigned to Illinois, United States. It is safe to answer or dial calls using this area code.
Area code 331 covers 22 cities and communities in Illinois, including Aurora, Bartlett, Bensenville, Big Rock, Downers Grove, and 17 more localities. This is based on telephone company rate center data — the geographic areas carriers use to determine local calling boundaries and to assign numbers when a business or individual requests a phone number in a specific city.
All numbers in the 331 area code observe Central Time (IANA timezone: America/Chicago). Central Time is UTC−6 in winter (CST) and UTC−5 in summer (CDT). When placing a call to a 331 number from a different time zone, check the current local time above to avoid calling outside of business hours.
From within Illinois, dial the 7-digit local number directly if calling within the same rate center, or dial 1 + 331 + 7-digit number for long-distance calls within North America. From outside the US or Canada, dial your country's international exit code followed by 1 331 XXX XXXX. The country code for both the United States and Canada in NANP is +1.
Format 331 numbers using E.164 notation as required by RFC 3966: prefix with +1 and omit dashes and parentheses (e.g., +13315550100). This format ensures tel: links work correctly on all mobile browsers and VoIP apps. See the tel: URI formatting guide for complete examples.