Area Code Detail

Area Code 331

Illinois (Aurora, Naperville, Oswego; western suburbs of Chicago) · In service since October 7, 2007

IL
Reports, 30 Days 259

Recent FCC and FTC complaint records tied to this area code.

Reports, 180 Days 1,923

Broader complaint volume used to prioritize indexable pages.

Active Prefixes 239

Distinct NPA-NXX prefixes surfaced from routing and assignment data.

Carriers / Assignees 37

Named carriers, assignees, or code holders found in routing data.

Cities / Rate Centers 24

Distinct cities or rate centers attached to this area code.

States / Territories 1

Coverage footprint visible from NANPA, pooled block, and Canada routing data.

North American Phone Intelligence

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Overview

What this area code covers

Illinois (Aurora, Naperville, Oswego; western suburbs of Chicago)

overlaid on 630

Common cities and rate centers

Aurora Bartlett Batavia Big Rock Downers Grove Elburn Elmhurst Geneva Glen Ellyn Hinsdale Itasca Kaneville Lemont Lombard Naperville Oswego Plano Roselle

Top carriers and assignees

  • ONVOY, LLC · 578 routing rows
  • T-MOBILE USA, INC. · 351 routing rows
  • NEW CINGULAR WIRELESS PCS, LLC - IL · 329 routing rows
  • CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL · 301 routing rows
  • BANDWIDTH.COM CLEC, LLC - IL · 177 routing rows
  • ONVOY SPECTRUM, LLC · 79 routing rows
  • PEERLESS NETWORK OF ILLINOIS, LLC - IL · 68 routing rows
  • COMCAST IP PHONE, LLC · 65 routing rows
  • LEVEL 3 COMMUNICATIONS, LLC - IL · 52 routing rows
  • FRACTEL, LLC · 52 routing rows
  • COMMIO, LLC · 48 routing rows
  • TELEPORT COMMUNICATIONS AMERICA, LLC - IL · 41 routing rows
NPA-NXX

Prefix directory inside area code 331

Each prefix below is collapsed to one primary locality row so you can scan the area code by prefix without the duplicated block-level assignment rows.

Prefix Primary Rate Center Primary City State
331-200-XXXX BARTLETT Bartlett IL
331-201-XXXX DOWNERSGRV Downers Grove IL
331-202-XXXX ELMHURST Elmhurst IL
331-203-XXXX AURORA Aurora IL
331-204-XXXX NAPERVILLE Naperville IL
331-205-XXXX AURORA Aurora IL
331-206-XXXX AURORA Aurora IL
331-207-XXXX YORKVILLE Yorkville IL
331-208-XXXX AURORA Aurora IL
331-209-XXXX ELMHURST Elmhurst IL
331-210-XXXX ST CHARLES Saint Charles IL
331-211-XXXX IL
331-212-XXXX AURORA Aurora IL
331-213-XXXX NAPERVILLE Naperville IL
331-214-XXXX DOWNERSGRV Downers Grove IL
331-215-XXXX NAPERVILLE Naperville IL
331-216-XXXX OSWEGO Oswego IL
331-217-XXXX LOMBARD Lombard IL
331-218-XXXX WHEATON Wheaton IL
331-219-XXXX AURORA Aurora IL
331-220-XXXX AURORA Aurora IL
331-221-XXXX ELMHURST Elmhurst IL
331-222-XXXX ST CHARLES Saint Charles IL
331-223-XXXX ST CHARLES Saint Charles IL
331-224-XXXX ITASCA Itasca IL
331-225-XXXX ELMHURST Elmhurst IL
331-226-XXXX NAPERVILLE Naperville IL
331-227-XXXX SUGARGROVE Sugar Grove IL
331-228-XXXX ST CHARLES Saint Charles IL
331-229-XXXX NAPERVILLE Naperville IL
331-230-XXXX AURORA Aurora IL
331-231-XXXX NAPERVILLE Naperville IL
331-232-XXXX W CHICAGO West Chicago IL
331-233-XXXX DOWNERSGRV Downers Grove IL
331-234-XXXX SUGARGROVE Sugar Grove IL
331-235-XXXX ST CHARLES Saint Charles IL
331-236-XXXX WHEATON Wheaton IL
331-237-XXXX NAPERVILLE Naperville IL
331-238-XXXX DOWNERSGRV Downers Grove IL
331-239-XXXX YORKVILLE Yorkville IL
331-240-XXXX W CHICAGO West Chicago IL
331-241-XXXX LOMBARD Lombard IL
331-242-XXXX LOMBARD Lombard IL
331-243-XXXX LOMBARD Lombard IL
331-244-XXXX NAPERVILLE Naperville IL
331-245-XXXX BARTLETT Bartlett IL
331-246-XXXX LEMONT Lemont IL
331-247-XXXX NAPERVILLE Naperville IL
331-248-XXXX GENEVA Geneva IL
331-249-XXXX NAPERVILLE Naperville IL
331-250-XXXX AURORA Aurora IL
331-251-XXXX DOWNERSGRV Downers Grove IL
331-252-XXXX WARRENVL Warrenville IL
331-253-XXXX LEMONT Lemont IL
331-254-XXXX SUGARGROVE Sugar Grove IL
331-255-XXXX AURORA Aurora IL
331-256-XXXX AURORA Aurora IL
331-257-XXXX AURORA Aurora IL
331-258-XXXX AURORA Aurora IL
331-259-XXXX SUGARGROVE Sugar Grove IL
331-260-XXXX DOWNERSGRV Downers Grove IL
331-261-XXXX LEMONT Lemont IL
331-262-XXXX AURORA Aurora IL
331-263-XXXX ITASCA Itasca IL
331-264-XXXX HINSDALE Hinsdale IL
331-265-XXXX GENEVA Geneva IL
331-266-XXXX ST CHARLES Saint Charles IL
331-267-XXXX LOMBARD Lombard IL
331-268-XXXX SUGARGROVE Sugar Grove IL
331-269-XXXX AURORA Aurora IL
331-270-XXXX AURORA Aurora IL
331-271-XXXX HINSDALE Hinsdale IL
331-272-XXXX ST CHARLES Saint Charles IL
331-273-XXXX LEMONT Lemont IL
331-274-XXXX AURORA Aurora IL
331-275-XXXX BARTLETT Bartlett IL
331-276-XXXX ST CHARLES Saint Charles IL
331-277-XXXX LOMBARD Lombard IL
331-278-XXXX AURORA Aurora IL
331-279-XXXX ELMHURST Elmhurst IL
331-280-XXXX DOWNERSGRV Downers Grove IL
331-281-XXXX NAPERVILLE Naperville IL
331-282-XXXX HINSDALE Hinsdale IL
331-283-XXXX GENEVA Geneva IL
331-284-XXXX BARTLETT Bartlett IL
331-285-XXXX NAPERVILLE Naperville IL
331-286-XXXX ST CHARLES Saint Charles IL
331-287-XXXX AURORA Aurora IL
331-288-XXXX ELBURN Elburn IL
331-289-XXXX HINSDALE Hinsdale IL
331-290-XXXX AURORA Aurora IL
331-291-XXXX DOWNERSGRV Downers Grove IL
331-292-XXXX DOWNERSGRV Downers Grove IL
331-293-XXXX AURORA Aurora IL
331-294-XXXX NAPERVILLE Naperville IL
331-295-XXXX AURORA Aurora IL
331-296-XXXX WHEATON Wheaton IL
331-297-XXXX BATAVIA Batavia IL
331-298-XXXX NAPERVILLE Naperville IL
331-299-XXXX HINSDALE Hinsdale IL
331-300-XXXX AURORA Aurora IL
331-301-XXXX AURORA Aurora IL
331-302-XXXX AURORA Aurora IL
331-303-XXXX ELBURN Elburn IL
331-304-XXXX BARTLETT Bartlett IL
331-305-XXXX NAPERVILLE Naperville IL
331-306-XXXX DOWNERSGRV Downers Grove IL
331-307-XXXX LOMBARD Lombard IL
331-308-XXXX BARTLETT Bartlett IL
331-309-XXXX LEMONT Lemont IL
331-310-XXXX BIG ROCK Big Rock IL
331-311-XXXX IL
331-312-XXXX AURORA Aurora IL
331-313-XXXX NAPERVILLE Naperville IL
331-314-XXXX ST CHARLES Saint Charles IL
331-315-XXXX LOMBARD Lombard IL
331-316-XXXX NAPERVILLE Naperville IL
331-317-XXXX HINSDALE Hinsdale IL
331-318-XXXX LEMONT Lemont IL
331-319-XXXX AURORA Aurora IL
331-320-XXXX BARTLETT Bartlett IL
331-321-XXXX AURORA Aurora IL
331-322-XXXX LOMBARD Lombard IL
331-323-XXXX GLEN ELLYN Glen Ellyn IL
331-324-XXXX YORKVILLE Yorkville IL
331-325-XXXX LEMONT Lemont IL
331-326-XXXX DOWNERSGRV Downers Grove IL
331-327-XXXX ST CHARLES Saint Charles IL
331-328-XXXX NAPERVILLE Naperville IL
331-329-XXXX AURORA Aurora IL
331-330-XXXX NAPERVILLE Naperville IL
331-331-XXXX AURORA Aurora IL
331-332-XXXX NAPERVILLE Naperville IL
331-333-XXXX NAPERVILLE Naperville IL
331-334-XXXX BATAVIA Batavia IL
331-335-XXXX ST CHARLES Saint Charles IL
331-336-XXXX AURORA Aurora IL
331-337-XXXX OSWEGO Oswego IL
331-338-XXXX AURORA Aurora IL
331-339-XXXX AURORA Aurora IL
331-340-XXXX ITASCA Itasca IL
331-341-XXXX PLANO Plano IL
331-342-XXXX NAPERVILLE Naperville IL
331-343-XXXX DOWNERSGRV Downers Grove IL
331-344-XXXX W CHICAGO West Chicago IL
331-345-XXXX NAPERVILLE Naperville IL
331-346-XXXX NAPERVILLE Naperville IL
331-347-XXXX WHEATON Wheaton IL
331-348-XXXX ELBURN Elburn IL
331-349-XXXX ST CHARLES Saint Charles IL
331-356-XXXX BARTLETT Bartlett IL
331-373-XXXX OSWEGO Oswego IL
331-385-XXXX AURORA Aurora IL
331-388-XXXX SUGARGROVE Sugar Grove IL
331-399-XXXX DOWNERSGRV Downers Grove IL
331-400-XXXX OSWEGO Oswego IL
331-401-XXXX NAPERVILLE Naperville IL
331-411-XXXX IL
331-422-XXXX ST CHARLES Saint Charles IL
331-425-XXXX AURORA Aurora IL
331-426-XXXX LEMONT Lemont IL
331-431-XXXX AURORA Aurora IL
331-442-XXXX ST CHARLES Saint Charles IL
331-444-XXXX NAPERVILLE Naperville IL
331-452-XXXX AURORA Aurora IL
331-454-XXXX AURORA Aurora IL
331-456-XXXX ROSELLE Roselle IL
331-457-XXXX NAPERVILLE Naperville IL
331-462-XXXX LOMBARD Lombard IL
331-465-XXXX W CHICAGO West Chicago IL
331-466-XXXX GLEN ELLYN Glen Ellyn IL
331-472-XXXX NAPERVILLE Naperville IL
331-481-XXXX DOWNERSGRV Downers Grove IL
331-500-XXXX GENEVA Geneva IL
331-511-XXXX IL
331-529-XXXX NAPERVILLE Naperville IL
331-551-XXXX LOMBARD Lombard IL
331-555-XXXX IL
331-575-XXXX AURORA Aurora IL
331-588-XXXX ST CHARLES Saint Charles IL
331-591-XXXX IL
331-600-XXXX WHEATON Wheaton IL
331-611-XXXX IL
331-625-XXXX DOWNERSGRV Downers Grove IL
331-627-XXXX LOMBARD Lombard IL
331-631-XXXX DOWNERSGRV Downers Grove IL
331-642-XXXX ELMHURST Elmhurst IL
331-643-XXXX AURORA Aurora IL
331-645-XXXX ELMHURST Elmhurst IL
331-666-XXXX AURORA Aurora IL
331-684-XXXX AURORA Aurora IL
331-688-XXXX NAPERVILLE Naperville IL
331-700-XXXX IL
331-701-XXXX NAPERVILLE Naperville IL
331-702-XXXX NAPERVILLE Naperville IL
331-703-XXXX W CHICAGO West Chicago IL
331-704-XXXX KANEVILLE Kaneville IL
331-707-XXXX AURORA Aurora IL
331-711-XXXX IL
331-716-XXXX WHEATON Wheaton IL
331-717-XXXX OSWEGO Oswego IL
331-725-XXXX OSWEGO Oswego IL
331-732-XXXX GENEVA Geneva IL
331-746-XXXX KANEVILLE Kaneville IL
331-757-XXXX LEMONT Lemont IL
331-758-XXXX AURORA Aurora IL
331-771-XXXX ST CHARLES Saint Charles IL
331-775-XXXX DOWNERSGRV Downers Grove IL
331-777-XXXX DOWNERSGRV Downers Grove IL
331-788-XXXX GENEVA Geneva IL
331-800-XXXX W CHICAGO West Chicago IL
331-801-XXXX DOWNERSGRV Downers Grove IL
331-803-XXXX LEMONT Lemont IL
331-806-XXXX WHEATON Wheaton IL
331-808-XXXX PLANO Plano IL
331-811-XXXX IL
331-814-XXXX NAPERVILLE Naperville IL
331-825-XXXX GENEVA Geneva IL
331-826-XXXX ELMHURST Elmhurst IL
331-837-XXXX W CHICAGO West Chicago IL
331-850-XXXX BIG ROCK Big Rock IL
331-866-XXXX WHEATON Wheaton IL
331-867-XXXX YORKVILLE Yorkville IL
331-871-XXXX W CHICAGO West Chicago IL
331-888-XXXX WARRENVL Warrenville IL
331-899-XXXX LOMBARD Lombard IL
331-900-XXXX ELMHURST Elmhurst IL
331-901-XXXX ST CHARLES Saint Charles IL
331-903-XXXX DOWNERSGRV Downers Grove IL
331-911-XXXX IL
331-946-XXXX GLEN ELLYN Glen Ellyn IL
331-950-XXXX IL
331-958-XXXX IL
331-959-XXXX IL
331-976-XXXX IL
331-979-XXXX ELMHURST Elmhurst IL
331-980-XXXX AURORA Aurora IL
331-998-XXXX DOWNERSGRV Downers Grove IL
331-999-XXXX OSWEGO Oswego IL
Recent Signals

Latest complaint activity tied to 331

Complaint pages are the strongest indexing opportunity for this site right now, especially for exact phone numbers and toll-free exchanges.

FTC report from MISSOURI

October 8, 2026 at 7:57 PM

331-296-6120 was logged as a live voice. Violation date: October 8, 2026 at 7:00 PM.

FTC report from Millington, TENNESSEE

October 8, 2026 at 5:23 PM

331-785-0970 was logged as a robocall. Violation date: October 8, 2026 at 12:02 PM.

FTC report from Westmont, ILLINOIS

October 8, 2026 at 4:02 PM

331-283-8864 was logged as a live voice. Violation date: October 8, 2026 at 12:06 PM.

FTC report from Bartlett, ILLINOIS

October 8, 2026 at 3:47 PM

331-267-9958 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 7, 2026 at 10:19 PM.

FTC report from Weston, FLORIDA

October 8, 2026 at 3:35 PM

331-777-1130 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 7, 2026 at 12:31 PM.

FTC report from Bristol, ARKANSAS

October 8, 2026 at 3:25 PM

331-236-2882 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: October 7, 2026 at 6:26 PM.

FTC report from VIRGINIA

October 8, 2026 at 3:08 PM

331-218-8204 was logged as a live voice. Violation date: October 8, 2026 at 3:03 PM.

FTC report from Geneva, ILLINOIS

October 8, 2026 at 12:42 PM

331-207-5675 was logged as a robocall. Category: Dropped call or no message. Violation date: October 8, 2026 at 11:39 AM.

FTC report from Tinley Park, ILLINOIS

October 8, 2026 at 12:22 PM

331-247-3190 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 8, 2026 at 11:19 AM.

FTC report from ILLINOIS

October 7, 2026 at 9:54 PM

331-212-9368 was logged as a live voice. Violation date: October 7, 2026 at 8:51 PM.

FTC report from Kanab, UTAH

October 7, 2026 at 9:11 PM

331-227-6598 was logged as a live voice. Category: Work from home & other ways to make money. Violation date: September 30, 2026 at 12:00 PM.

FTC report from Pauls Valley, OKLAHOMA

October 7, 2026 at 8:04 PM

331-256-8368 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 7, 2026 at 8:22 AM.

FTC report from Berwyn, ILLINOIS

October 7, 2026 at 5:15 PM

331-202-0392 was logged as a live voice. Violation date: October 7, 2026 at 4:08 PM.

FTC report from Weston, FLORIDA

October 7, 2026 at 3:48 PM

331-777-1130 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 7, 2026 at 12:31 PM.

FTC report from Lockport, ILLINOIS

October 7, 2026 at 3:13 PM

331-356-5369 was logged as a unwanted call. Violation date: October 7, 2026 at 2:11 PM.

FTC report from Fernandina, FLORIDA

October 7, 2026 at 1:59 PM

331-888-9143 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 7, 2026 at 12:01 AM.

FTC report from Dayton, OHIO

October 7, 2026 at 10:20 AM

331-216-1963 was logged as a live voice. Category: Calls pretending to be government, businesses, or family and friends. Violation date: October 6, 2026 at 1:57 PM.

FTC report from MICHIGAN

October 7, 2026 at 8:53 AM

331-800-2557 was logged as a robocall. Violation date: October 7, 2026 at 6:55 AM.

FTC report from ILLINOIS

October 6, 2026 at 9:45 PM

331-266-6269 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: October 6, 2026 at 8:28 PM.

FTC report from Phoenix, ARIZONA

October 6, 2026 at 8:55 PM

331-341-1515 was logged as a live voice. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 6, 2026 at 5:49 PM.

FTC report from Poplar Grove, ILLINOIS

October 6, 2026 at 7:45 PM

331-356-5016 was logged as a live voice. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 6, 2026 at 10:00 PM.

FTC report from ILLINOIS

October 6, 2026 at 7:32 PM

331-296-6661 was logged as a live voice. Violation date: October 6, 2026 at 11:06 AM.

FTC report from ILLINOIS

October 6, 2026 at 7:19 PM

331-296-6665 was logged as a live voice. Violation date: October 2, 2026 at 4:10 PM.

FTC report from Palm Coast, FLORIDA

October 6, 2026 at 5:52 PM

331-867-1079 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 6, 2026 at 5:13 PM.

FTC report from Chicago, ILLINOIS

October 6, 2026 at 5:42 PM

331-324-8609 was logged as a live voice. Category: Work from home & other ways to make money. Violation date: October 6, 2026 at 4:38 PM.

FTC report from Bolingbrook, ILLINOIS

October 6, 2026 at 5:20 PM

331-345-6097 was logged as a live voice. Category: Home improvement & cleaning. Violation date: October 6, 2026 at 3:39 PM.

FTC report from CALIFORNIA

October 6, 2026 at 3:37 PM

331-529-3290 was logged as a robocall. Category: No Subject Provided. Violation date: September 28, 2026 at 6:14 PM.

FTC report from Berwyn, ILLINOIS

October 6, 2026 at 3:28 PM

331-202-0354 was logged as a live voice. Violation date: October 5, 2026 at 5:08 PM.

FTC report from Bradenton, FLORIDA

October 6, 2026 at 12:14 PM

331-465-8676 was logged as a live voice. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 6, 2026 at 12:08 PM.

FTC report from OKLAHOMA

October 6, 2026 at 10:54 AM

331-212-9278 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: October 6, 2026 at 1:42 PM.

FTC report from ILLINOIS

October 6, 2026 at 12:57 AM

331-202-3239 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: October 5, 2026 at 5:41 PM.

FTC report

October 5, 2026 at 8:53 PM

331-202-0701 was logged as a unwanted call. Violation date: October 1, 2026 at 12:00 AM.

FTC report from VIRGINIA

October 5, 2026 at 3:33 PM

331-600-6393 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: September 24, 2026 at 11:51 AM.

FTC report from ILLINOIS

October 5, 2026 at 3:28 PM

331-202-3253 was logged as a live voice. Violation date: October 5, 2026 at 2:20 PM.

FTC report from Bartlett, ILLINOIS

October 5, 2026 at 1:10 PM

331-342-3635 was logged as a live voice. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 1, 2026 at 5:09 PM.

FTC report from Collingswood, NEW JERSEY

October 4, 2026 at 11:00 PM

331-356-9938 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: September 30, 2026 at 1:47 PM.

FTC report from WASHINGTON

October 4, 2026 at 5:36 PM

331-296-1080 was logged as a live voice. Violation date: September 28, 2026 at 4:29 PM.

FTC report from ARIZONA

October 4, 2026 at 1:26 PM

331-268-0621 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 2, 2026 at 4:13 PM.

FTC report from Nc, NORTH CAROLINA

October 4, 2026 at 10:32 AM

331-400-4633 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 3, 2026 at 12:00 AM.

FTC report from Frankfort, ILLINOIS

October 3, 2026 at 9:05 PM

331-266-6685 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 1, 2026 at 4:09 PM.