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Area Code Detail

Area Code 331

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

IL
Reports, 30 Days 163

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

Reports, 180 Days 1,140

Broader complaint volume used to prioritize indexable pages.

Active Prefixes 236

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

Carriers / Assignees 35

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

Search a phone number, area code, exchange, or short code

Paste raw digits, a formatted phone number, an area code, an NPA-NXX block, or a short code. US and Canada phone lookups route automatically, and international iMessage checks are available separately.

Phone LookupTop ComplaintsArea CodesNPA-NXXiMessage
Examples: 206-739-5800, 206, 206-739, 48369
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 · 562 routing rows
  • T-MOBILE USA, INC. · 363 routing rows
  • NEW CINGULAR WIRELESS PCS, LLC - IL · 316 routing rows
  • CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL · 293 routing rows
  • BANDWIDTH.COM CLEC, LLC - IL · 174 routing rows
  • ONVOY SPECTRUM, LLC · 82 routing rows
  • PEERLESS NETWORK OF ILLINOIS, LLC - IL · 67 routing rows
  • COMCAST IP PHONE, LLC · 65 routing rows
  • FRACTEL, LLC · 54 routing rows
  • LEVEL 3 COMMUNICATIONS, LLC - IL · 48 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
331-348-XXXX ELBURN Elburn 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 Hewitt, NEW JERSEY

May 19, 2026 at 8:16 PM

331-224-3634 was logged as a robocall. Category: Dropped call or no message. Violation date: May 19, 2026 at 10:03 AM.

FTC report from San Marcos, CALIFORNIA

May 19, 2026 at 7:14 PM

331-267-6158 was logged as a robocall. Violation date: May 19, 2026 at 3:43 PM.

FTC report from Chesterton, INDIANA

May 19, 2026 at 4:54 PM

331-258-7077 was logged as a unwanted call. Violation date: April 1, 2026 at 12:00 AM.

FTC report from ILLINOIS

May 19, 2026 at 4:45 PM

331-399-0047 was logged as a robocall. Violation date: May 19, 2026 at 3:36 PM.

FTC report from Aurora, ILLINOIS

May 19, 2026 at 4:25 PM

331-227-5438 was logged as a live voice. Violation date: May 19, 2026 at 3:20 AM.

FTC report from Daytona Beach, KANSAS

May 19, 2026 at 3:33 PM

331-373-3074 was logged as a robocall. Violation date: May 15, 2026 at 12:55 PM.

FTC report from Baton Rouge, LOUISIANA

May 19, 2026 at 2:25 PM

331-210-9422 was logged as a robocall. Violation date: April 15, 2026 at 3:45 PM.

FTC report from Fair Lawn, NEW JERSEY

May 19, 2026 at 11:27 AM

331-373-3095 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: May 15, 2026 at 12:26 PM.

FTC report from ILLINOIS

May 19, 2026 at 8:28 AM

331-212-9185 was logged as a live voice. Category: Dropped call or no message. Violation date: May 18, 2026 at 3:54 PM.

FTC report from Wheaton, ILLINOIS

May 18, 2026 at 9:41 PM

331-266-6597 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: May 6, 2026 at 9:28 AM.

FTC report from Virginia Beach, VIRGINIA

May 18, 2026 at 9:16 PM

331-500-4217 was logged as a live voice. Violation date: May 18, 2026 at 8:53 PM.

FTC report from ILLINOIS

May 18, 2026 at 2:01 PM

331-268-1426 was logged as a robocall. Violation date: May 18, 2026 at 11:02 AM.

FTC report from Dieterich, ILLINOIS

May 18, 2026 at 12:08 PM

331-306-6506 was logged as a robocall. Violation date: May 14, 2026 at 1:04 PM.

FTC report from Dieterich, ILLINOIS

May 18, 2026 at 12:04 PM

331-306-6506 was logged as a robocall. Violation date: May 9, 2026 at 9:29 AM.

FTC report from Oak Brook, ILLINOIS

May 18, 2026 at 12:00 PM

331-290-9715 was logged as a live voice. Category: Home security & alarms. Violation date: May 18, 2026 at 10:43 AM.

FTC report from Dieterich, ILLINOIS

May 18, 2026 at 11:59 AM

331-306-6506 was logged as a robocall. Violation date: May 5, 2026 at 9:23 AM.

FTC report from Naperville, ILLINOIS

May 18, 2026 at 11:02 AM

331-204-3024 was logged as a robocall. Violation date: April 24, 2026 at 11:18 AM.

FTC report from Naperville, ILLINOIS

May 18, 2026 at 10:58 AM

331-286-5641 was logged as a robocall. Violation date: April 27, 2026 at 10:00 AM.

FTC report from Naperville, ILLINOIS

May 18, 2026 at 10:57 AM

331-217-3749 was logged as a robocall. Violation date: April 27, 2026 at 12:34 PM.

FTC report from Naperville, ILLINOIS

May 17, 2026 at 10:20 PM

331-286-5441 was logged as a robocall. Violation date: May 4, 2026 at 12:36 PM.

FTC report from Naperville, ILLINOIS

May 17, 2026 at 10:19 PM

331-286-5921 was logged as a robocall. Violation date: May 4, 2026 at 1:52 PM.

FTC report from ILLINOIS

May 16, 2026 at 3:02 PM

331-336-4686 was logged as a live voice. Violation date: May 12, 2026 at 5:02 PM.

FTC report from Roscoe, NEW YORK

May 16, 2026 at 1:52 PM

331-808-9053 was logged as a live voice. Violation date: May 16, 2026 at 1:45 PM.

FTC report from MASSACHUSETTS

May 16, 2026 at 12:40 PM

331-248-4762 was logged as a robocall. Violation date: April 13, 2026 at 10:27 AM.

FTC report from SOUTH CAROLINA

May 15, 2026 at 4:49 PM

331-373-3641 was logged as a unwanted call. Category: No Subject Provided. Violation date: May 12, 2026 at 12:00 AM.

FTC report from Mentor, OHIO

May 15, 2026 at 4:47 PM

331-356-7753 was logged as a robocall. Violation date: May 11, 2026 at 6:43 PM.

FTC report from Not Provided, ILLINOIS

May 15, 2026 at 4:24 PM

331-308-0521 was logged as a robocall. Category: Medical & prescriptions. Violation date: May 15, 2026 at 12:00 AM.

FTC report from ILLINOIS

May 15, 2026 at 2:25 PM

331-732-5712 was logged as a unwanted call. Category: No Subject Provided. Violation date: May 4, 2026 at 12:00 AM.

FTC report from Decatur, ILLINOIS

May 15, 2026 at 2:02 PM

331-255-0172 was logged as a robocall. Violation date: May 15, 2026 at 12:16 PM.

FTC report from San Antonio, TEXAS

May 15, 2026 at 1:20 PM

331-283-4090 was logged as a live voice. Category: Lotteries, prizes & sweepstakes. Violation date: May 15, 2026 at 12:09 PM.

FTC report from Rochester, NEW YORK

May 15, 2026 at 12:37 PM

331-373-3719 was logged as a robocall. Violation date: May 15, 2026 at 9:06 AM.

FTC report from Smithtown, NEW YORK

May 15, 2026 at 12:26 PM

331-373-3082 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: May 15, 2026 at 11:17 AM.

FTC report from INDIANA

May 15, 2026 at 10:42 AM

331-256-5069 was logged as a robocall. Category: Vacation & timeshares. Violation date: May 14, 2026 at 11:00 AM.

FTC report from ILLINOIS

May 14, 2026 at 3:29 PM

331-266-1281 was logged as a unwanted call. Violation date: May 12, 2026 at 1:47 PM.

FTC report from CALIFORNIA

May 14, 2026 at 1:49 PM

331-373-3182 was logged as a robocall. Violation date: May 7, 2026 at 10:52 AM.

FTC report from Naperville, ILLINOIS

May 14, 2026 at 12:50 PM

331-284-6984 was logged as a robocall. Violation date: May 7, 2026 at 12:33 PM.

FTC report from Naperville, ILLINOIS

May 14, 2026 at 12:49 PM

331-202-2811 was logged as a live voice. Category: Warranties & protection plans. Violation date: May 8, 2026 at 11:14 AM.

FTC report from Naperville, ILLINOIS

May 14, 2026 at 12:46 PM

331-204-3676 was logged as a robocall. Violation date: May 8, 2026 at 12:23 PM.

FTC report from Naperville, ILLINOIS

May 14, 2026 at 12:45 PM

331-204-1218 was logged as a robocall. Violation date: May 11, 2026 at 9:42 AM.

FTC report from Naperville, ILLINOIS

May 14, 2026 at 12:43 PM

331-204-3634 was logged as a robocall. Violation date: May 11, 2026 at 2:46 PM.