Area Code 331
Area code 331 is in Illinois, USA , spanning 5 counties and serving 53 cities, including Aurora, Wheaton or Downers Grove; it currently uses 216 prefixes, assigned from 331-200-XXXX through 331-999-XXXX.
In service since October 07, 2007, area code 331 is an overlay Numbering Plan Area, part of overlay complex 630/331.
The current local time is .
For exact NPA boundaries see official 331 area code map
Phone number lookup
More Illinois area codes:
Locate any 331-NXX prefix:
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 331-200 | Bartlett | 7/11/2011 |
| 331-201 | Downers Grove | 1/6/2012 |
| 331-202 | Elmhurst | 1/17/2012 |
| 331-203 | Aurora | 10/12/2011 |
| 331-204 | Naperville | 12/10/2015 |
| 331-205 | Aurora | 10/21/2011 |
| 331-206 | Aurora | 10/12/2011 |
| 331-207 | Yorkville | 11/1/2011 |
| 331-208 | Aurora | 11/8/2011 |
| 331-209 | Elmhurst | 1/17/2012 |
| 331-210 | St Charles | 3/6/2012 |
| 331-212 | Aurora | 4/5/2012 |
| 331-213 | Naperville | 9/6/2011 |
| 331-214 | Downers Grove | 6/20/2012 |
| 331-215 | Naperville | 9/28/2012 |
| 331-216 | Oswego | 10/31/2012 |
| 331-217 | Lombard | 07/11/2023 |
| 331-218 | Wheaton | 7/9/2013 |
| 331-219 | Aurora | 3/16/2017 |
| 331-220 | Aurora | 7/12/2011 |
| 331-221 | Elmhurst | 1/21/2009 |
| 331-222 | St Charles | 10/28/2008 |
| 331-223 | St Charles | 10/28/2008 |
| 331-224 | Itasca | 06/05/2023 |
| 331-225 | Elmhurst | 8/22/2011 |
| 331-226 | Naperville | 3/20/2017 |
| 331-227 | Sugar Grove | 5/17/2016 |
| 331-228 | St Charles | 9/21/2011 |
| 331-229 | Naperville | 11/27/2012 |
| 331-230 | Aurora | 4/5/2017 |
| 331-231 | Naperville | 8/7/2017 |
| 331-232 | West Chicago | 8/8/2017 |
| 331-233 | Downers Grove | 3/13/2017 |
| 331-234 | Sugar Grove | 7/8/2013 |
| 331-235 | St Charles | 10/17/2017 |
| 331-236 | Wheaton | 4/5/2017 |
| 331-237 | Naperville | 11/7/2017 |
| 331-238 | Downers Grove | 12/19/2017 |
| 331-239 | Yorkville | 8/27/2018 |
| 331-240 | West Chicago | 4/10/2013 |
| 331-241 | Lombard | 10/16/2018 |
| 331-242 | Lombard | 10/19/2018 |
| 331-243 | Lombard | 10/19/2018 |
| 331-244 | Naperville | 9/21/2017 |
| 331-245 | Bartlett | 4/18/2013 |
| 331-246 | Lemont | 10/19/2018 |
| 331-247 | Naperville | 11/21/2018 |
| 331-248 | Geneva | 7/6/2007 |
| 331-249 | Naperville | 12/5/2018 |
| 331-250 | Aurora | 4/10/2012 |
| 331-251 | Downers Grove | 12/5/2012 |
| 331-252 | Warrenville | 6/2/2016 |
| 331-253 | Lemont | 10/27/2014 |
| 331-254 | Sugar Grove | 7/16/2014 |
| 331-255 | Aurora | 8/22/2017 |
| 331-256 | Aurora | 9/13/2011 |
| 331-257 | Aurora | 1/17/2020 |
| 331-258 | Aurora | N/A |
| 331-259 | Sugar Grove | N/A |
| 331-260 | Downers Grove | 2/25/2019 |
| 331-261 | Lemont | 6/20/2019 |
| 331-262 | Aurora | 7/30/2008 |
| 331-263 | Itasca | 3/11/2016 |
| 331-264 | Hinsdale | 3/6/2020 |
| 331-265 | Geneva | N/A |
| 331-266 | St Charles | 4/10/2020 |
| 331-267 | Lombard | 9/18/2020 |
| 331-268 | Sugar Grove | 1/14/2021 |
| 331-269 | Aurora | 5/14/2021 |
| 331-270 | Aurora | 7/20/2021 |
| 331-271 | Hinsdale | 10/21/2020 |
| 331-272 | St Charles | 7/15/2021 |
| 331-273 | Lemont | 6/9/2021 |
| 331-274 | Aurora | 8/3/2021 |
| 331-275 | Bartlett | 8/3/2021 |
| 331-276 | St Charles | 11/10/2014 |
| 331-277 | Lombard | 8/6/2021 |
| 331-278 | Aurora | 8/13/2021 |
| 331-279 | Elmhurst | 10/15/2021 |
| 331-280 | Downers Grove | 12/29/2021 |
| 331-281 | Naperville | 10/25/2012 |
| 331-282 | Hinsdale | 12/10/2021 |
| 331-283 | Geneva | 2/23/2022 |
| 331-284 | Bartlett | 3/11/2022 |
| 331-285 | Naperville | 5/4/2022 |
| 331-286 | St Charles | 7/15/2022 |
| 331-287 | Aurora | 7/20/2022 |
| 331-288 | Elburn | 2/17/2022 |
| 331-289 | Hinsdale | 8/12/2022 |
| 331-290 | Aurora | 8/26/2022 |
| 331-291 | Downers Grove | 8/26/2022 |
| 331-292 | Downers Grove | 10/14/2022 |
| 331-293 | Aurora | 01/10/2023 |
| 331-294 | Naperville | 01/12/2023 |
| 331-295 | Aurora | 02/07/2023 |
| 331-296 | Wheaton | 04/18/2023 |
| 331-297 | Batavia | 08/09/2023 |
| 331-298 | Naperville | 08/09/2023 |
| 331-299 | Hinsdale | 1/4/2021 |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 331-300 | Aurora | 3/17/2016 |
| 331-301 | Aurora | 3/13/2013 |
| 331-302 | Aurora | 2/11/2013 |
| 331-303 | Elburn | N/A |
| 331-304 | Bartlett | 2/20/2015 |
| 331-305 | Naperville | 8/15/2013 |
| 331-306 | Downers Grove | 09/19/2023 |
| 331-307 | Lombard | 10/13/2014 |
| 331-308 | Bartlett | 12/23/2014 |
| 331-309 | Lemont | 09/26/2023 |
| 331-310 | Big Rock | 12/29/2014 |
| 331-312 | Aurora | 11/06/2023 |
| 331-313 | Naperville | 8/16/2022 |
| 331-314 | St Charles | 11/17/2023 |
| 331-315 | Lombard | 8/8/2016 |
| 331-316 | Naperville | 01/04/2024 |
| 331-317 | Hinsdale | 01/05/2024 |
| 331-318 | Lemont | 8/1/2013 |
| 331-319 | Aurora | 01/24/2024 |
| 331-320 | Bartlett | 01/30/2024 |
| 331-321 | Aurora | 7/20/2015 |
| 331-322 | Lombard | 02/08/2024 |
| 331-323 | Glen Ellyn | 02/08/2024 |
| 331-324 | Yorkville | 03/13/2024 |
| 331-325 | Lemont | 03/21/2024 |
| 331-326 | Downers Grove | 03/28/2024 |
| 331-327 | St Charles | 11/14/2024 |
| 331-328 | Naperville | 12/16/2024 |
| 331-329 | Aurora | 01/08/2025 |
| 331-330 | Naperville | 8/19/2008 |
| 331-332 | Naperville | 11/3/2008 |
| 331-333 | Naperville | 11/3/2008 |
| 331-334 | Batavia | 6/2/2021 |
| 331-335 | St Charles | 04/30/2024 |
| 331-336 | Aurora | 10/11/2019 |
| 331-337 | Oswego | 01/09/2025 |
| 331-338 | Aurora | 01/29/2025 |
| 331-341 | Plano | 3/30/2021 |
| 331-343 | Downers Grove | 01/13/2023 |
| 331-345 | Naperville | 11/18/2020 |
| 331-348 | Elburn | 10/11/2019 |
| 331-356 | Bartlett | 10/10/2019 |
| 331-373 | Oswego | 2/25/2022 |
| 331-385 | Aurora | 9/28/2016 |
| 331-388 | Sugar Grove | 1/25/2021 |
| 331-399 | Downers Grove | 1/22/2021 |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 331-400 | Oswego | 8/8/2019 |
| 331-401 | Naperville | 12/14/2015 |
| 331-422 | St Charles | 11/13/2008 |
| 331-425 | Aurora | 7/11/2007 |
| 331-426 | Lemont | 2/18/2022 |
| 331-431 | Aurora | 5/26/2010 |
| 331-442 | St Charles | 10/30/2008 |
| 331-444 | Naperville | 8/4/2010 |
| 331-452 | Aurora | 9/20/2007 |
| 331-454 | Aurora | 5/7/2009 |
| 331-456 | Roselle | 12/5/2007 |
| 331-457 | Naperville | 11/14/2008 |
| 331-462 | Lombard | 8/23/2008 |
| 331-465 | West Chicago | 10/17/2007 |
| 331-466 | Glen Ellyn | 2/17/2022 |
| 331-472 | Naperville | 10/22/2008 |
| 331-481 | Downers Grove | 10/29/2008 |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 331-701 | Naperville | 12/11/2014 |
| 331-702 | Naperville | 10/23/2013 |
| 331-703 | West Chicago | 10/24/2013 |
| 331-704 | Kaneville | 4/21/2015 |
| 331-707 | Aurora | 8/23/2016 |
| 331-716 | Wheaton | 1/18/2016 |
| 331-717 | Oswego | 1/18/2016 |
| 331-725 | Oswego | N/A |
| 331-732 | Geneva | 10/11/2019 |
| 331-746 | Kaneville | 2/17/2022 |
| 331-757 | Lemont | 7/13/2016 |
| 331-758 | Aurora | 10/27/2021 |
| 331-771 | St Charles | 2/10/2016 |
| 331-775 | Downers Grove | 1/4/2016 |
| 331-777 | Downers Grove | 9/22/2010 |
| 331-788 | Geneva | 1/25/2021 |
| NPANXX | Area Served1 | Date1 |
|---|---|---|
| 331-800 | West Chicago | 9/29/2017 |
| 331-801 | Downers Grove | 5/15/2014 |
| 331-803 | Lemont | 4/10/2013 |
| 331-806 | Wheaton | 6/11/2015 |
| 331-808 | Plano | 6/5/2015 |
| 331-814 | Naperville | 6/25/2015 |
| 331-825 | Geneva | N/A |
| 331-826 | Elmhurst | 11/18/2008 |
| 331-837 | West Chicago | 1/7/2022 |
| 331-850 | Big Rock | 3/30/2021 |
| 331-866 | Wheaton | 1/13/2022 |
| 331-867 | Yorkville | 7/14/2020 |
| 331-871 | West Chicago | 2/17/2016 |
| 331-888 | Warrenville | 9/24/2010 |
| 331-899 | Lombard | 12/22/2020 |
- For 'Area served' we list the rate center. In the North American Numbering Plan a rate center is a geographic area used to determine local calling boundaries for billing purposes. Its name is generally a locality, often not the only one served by an NPA-NXX combination.
- Assignment date. N/A - mostly central office codes assigned before 2001.
- NXX prefixes last updated: June 3, 2025
Cities in area code 331
| City1 | County | Time Zone1 |
|---|---|---|
| Addison | Dupage | C |
| Aurora | Kane | C |
| Bartlett | Dupage | C |
| Batavia | Kane | C |
| Bensenville | Dupage | C |
| Big Rock | Kane | C |
| Bloomingdale | Dupage | C |
| Bolingbrook | Will | C |
| Bristol | Kendall | C |
| Carol Stream | Dupage | C |
| Clarendon Hills | Dupage | C |
| Darien | Dupage | C |
| Downers Grove | Dupage | C |
| Elburn | Kane | C |
| Elmhurst | Dupage | C |
| Eola | Dupage | C |
| Fox Valley | Dupage | C |
| Geneva | Kane | C |
| Glen Ellyn | Dupage | C |
| Glendale Heights | Dupage | C |
| Hanover Park | Cook | C |
| Hinsdale | Dupage | C |
| Itasca | Dupage | C |
| Kaneville | Kane | C |
| Lafox | Kane | C |
| Lemont | Cook | C |
| Lisle | Dupage | C |
| Lombard | Dupage | C |
| Medinah | Dupage | C |
| Millbrook | Kendall | C |
| Montgomery | Kendall | C |
| Mooseheart | Kane | C |
| Naperville | Will | C |
| North Aurora | Kane | C |
| Oak Brook | Dupage | C |
| Oswego | Kendall | C |
| Plano | Kendall | C |
| Roselle | Dupage | C |
| St Charles | Kane | C |
| Streamwood | Cook | C |
| Sugar Grove | Kane | C |
| Villa Park | Dupage | C |
| Warrenville | Dupage | C |
| Wasco | Kane | C |
| Wayne | Dupage | C |
| West Chicago | Dupage | C |
| Westmont | Dupage | C |
| Wheaton | Dupage | C |
| Willowbrook | Dupage | C |
| Winfield | Dupage | C |
| Wood Dale | Dupage | C |
| Woodridge | Dupage | C |
| Yorkville | Kendall | C |
- Listed above are most places served by USA area code 331. When multiple places in a US state share the same name we list the largest one only. Cities with population over 50,000 are displayed in bold text.
- C stands for Central Time (currently ).