Area Code 331

Area code 331 serves the state of Illinois. This area code was assigned on July 23rd, 1999. On October 7th, 2007 it went into service. 331 is a General Purpose Code. 331 service area does overlap with 630 area codes. Dialing pattern for local calls within the same NPA (area code) is 1+10D.

Active Prefixes in Area Code 331

Prefix Primary City
331-200 Hanover Park
331-201 Downers Grove
331-202 Elmhurst
331-203 Aurora
331-205 Aurora
331-206 Aurora
331-207 Yorkville
331-208 Aurora
331-209 Elmhurst
331-210 Illinois
331-212 Aurora
331-213 Naperville
331-214 Downers Grove
331-215 Naperville
331-216 Oswego
331-218 Wheaton
331-220 Aurora
331-221 Elmhurst
331-222 Illinois
331-223 Illinois
331-225 Elmhurst
331-228 Illinois
331-229 Naperville
331-234 Sugar Grove
331-240 West Chicago
331-245 Hanover Park
331-248 Geneva
331-250 Aurora
331-251 Downers Grove
331-253 Lemont
331-254 Sugar Grove
331-256 Aurora
331-262 Aurora
331-276 Illinois
331-281 Naperville
331-301 Aurora
331-302 Aurora
331-303 Elburn
331-304 Hanover Park
331-305 Naperville
331-307 Lombard
331-308 Hanover Park
331-310 Big Rock
331-318 Lemont
331-321 Aurora
331-330 Montgomery
331-332 Naperville
331-333 Naperville
331-422 Illinois
331-425 Aurora
331-431 Aurora
331-442 Illinois
331-444 Naperville
331-452 Aurora
331-454 Aurora
331-456 Roselle
331-457 Naperville
331-462 Lombard
331-465 West Chicago
331-472 Naperville
331-481 Downers Grove
331-551 Lombard
331-575 Aurora
331-588 Illinois
331-625 Downers Grove
331-642 Elmhurst
331-643 Aurora
331-645 Elmhurst
331-684 Aurora
331-701 Naperville
331-702 Naperville
331-703 West Chicago
331-704 Sugar Grove
331-725 Oswego
331-777 Downers Grove
331-801 Downers Grove
331-803 Lemont
331-806 Wheaton
331-808 Plano
331-814 Naperville
331-825 Kane
331-826 Elmhurst
331-888 Warrenville
331-901 Illinois
331-903 Downers Grove
331-979 Elmhurst
331-980 Aurora
331-998 Downers Grove
331-999 Oswego