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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 292

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

Reports, 180 Days 1,099

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 Algonquin, ILLINOIS

April 29, 2026 at 10:32 PM

331-688-2371 was logged as a robocall. Violation date: April 29, 2026 at 10:32 AM.

FTC report from ILLINOIS

April 29, 2026 at 5:41 PM

331-320-2287 was logged as a robocall. Category: Dropped call or no message. Violation date: April 29, 2026 at 2:14 PM.

FTC report from Pueblo West, COLORADO

April 29, 2026 at 4:14 PM

331-808-9833 was logged as a robocall. Violation date: April 29, 2026 at 2:11 PM.

FTC report from Beverly, MASSACHUSETTS

April 29, 2026 at 3:50 PM

331-212-8085 was logged as a robocall. Violation date: April 17, 2026 at 7:02 PM.

FTC report from Belleville, TEXAS

April 29, 2026 at 2:56 PM

331-981-8651 was logged as a live voice. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: April 29, 2026 at 1:50 PM.

FTC report from Gainesville, VIRGINIA

April 29, 2026 at 2:44 PM

331-373-3316 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: April 20, 2026 at 12:00 AM.

FTC report from Conyers, GEORGIA

April 29, 2026 at 1:23 PM

331-296-6946 was logged as a robocall. Violation date: April 29, 2026 at 1:23 PM.

FTC report from ILLINOIS

April 29, 2026 at 9:55 AM

331-356-8212 was logged as a robocall. Category: Dropped call or no message. Violation date: April 28, 2026 at 4:23 PM.

FTC report from Oakley, KANSAS

April 28, 2026 at 7:02 PM

331-803-1710 was logged as a robocall. Violation date: April 28, 2026 at 5:54 PM.

FTC report from Oklahoma City, OKLAHOMA

April 28, 2026 at 6:02 PM

331-306-2713 was logged as a robocall. Category: Dropped call or no message. Violation date: April 28, 2026 at 1:33 PM.

FTC report from Jackson, MISSISSIPPI

April 27, 2026 at 12:32 PM

331-319-8513 was logged as a robocall. Category: Lotteries, prizes & sweepstakes. Violation date: April 3, 2026 at 3:04 AM.

FTC report from LOUISIANA

April 27, 2026 at 4:23 AM

This report was logged as a live voice. Category: Dropped call or no message. Violation date: April 16, 2026 at 3:23 PM.

FTC report from ILLINOIS

April 26, 2026 at 9:16 PM

This report was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: March 31, 2026 at 8:10 PM.

FTC report from Williamsport, PENNSYLVANIA

April 26, 2026 at 4:21 PM

331-837-4067 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: April 26, 2026 at 3:30 PM.

FTC report from PENNSYLVANIA

April 25, 2026 at 6:17 PM

331-272-6706 was logged as a robocall. Category: No Subject Provided. Violation date: March 24, 2026 at 4:01 PM.

FTC report from Aurora, ILLINOIS

April 24, 2026 at 4:12 PM

331-373-3705 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: April 22, 2026 at 1:40 PM.

FTC report from Bolingbrook, ILLINOIS

April 24, 2026 at 3:50 PM

331-232-2901 was logged as a unwanted call. Violation date: April 24, 2026 at 2:46 PM.

FTC report from Spencer, MASSACHUSETTS

April 24, 2026 at 1:58 PM

331-837-4306 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: April 24, 2026 at 10:07 AM.

FTC report from MARYLAND

April 24, 2026 at 12:17 PM

331-373-3069 was logged as a robocall. Violation date: April 24, 2026 at 12:09 PM.

FTC report from NEW YORK

April 24, 2026 at 11:57 AM

331-529-3623 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: April 24, 2026 at 11:07 AM.

FTC report from Bloomington, ILLINOIS

April 24, 2026 at 10:23 AM

331-356-8968 was logged as a robocall. Violation date: April 24, 2026 at 8:15 AM.

FTC report from OREGON

April 23, 2026 at 5:17 PM

331-837-4095 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: April 21, 2026 at 4:10 PM.

FTC report from ALABAMA

April 23, 2026 at 3:26 PM

331-210-9503 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: April 18, 2026 at 5:23 PM.

FTC report from ILLINOIS

April 23, 2026 at 3:05 PM

331-266-6455 was logged as a robocall. Category: Dropped call or no message. Violation date: April 23, 2026 at 2:01 PM.

FTC report from Tallahassee, FLORIDA

April 23, 2026 at 1:14 PM

331-356-7847 was logged as a live voice. Category: Calls pretending to be government, businesses, or family and friends. Violation date: April 23, 2026 at 1:11 PM.

FTC report from Spring Lake, MICHIGAN

April 23, 2026 at 12:14 PM

331-267-7076 was logged as a robocall. Violation date: April 23, 2026 at 10:34 AM.

FTC report from Ogden Dunes, INDIANA

April 23, 2026 at 11:25 AM

331-286-5473 was logged as a live voice. Category: Dropped call or no message. Violation date: April 23, 2026 at 10:18 AM.

FTC report from ILLINOIS

April 23, 2026 at 11:07 AM

331-336-4801 was logged as a live voice. Violation date: April 22, 2026 at 5:46 PM.

FTC report from Parks, ARIZONA

April 22, 2026 at 4:55 PM

331-268-0569 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: April 22, 2026 at 4:00 AM.

FTC report from ILLINOIS

April 22, 2026 at 3:18 PM

331-207-4290 was logged as a robocall. Violation date: April 21, 2026 at 12:07 PM.

FTC report from Angola, NEW YORK

April 22, 2026 at 3:18 PM

331-238-6441 was logged as a live voice. Category: Calls pretending to be government, businesses, or family and friends. Violation date: April 22, 2026 at 10:33 AM.

FTC report from Inverness, ILLINOIS

April 22, 2026 at 2:52 PM

331-296-5318 was logged as a live voice. Category: Home improvement & cleaning. Violation date: April 22, 2026 at 1:48 PM.

FTC report from Westchester, ILLINOIS

April 22, 2026 at 2:14 PM

331-272-5307 was logged as a robocall. Category: Dropped call or no message. Violation date: April 22, 2026 at 1:11 PM.

FTC report from Clinton, ILLINOIS

April 22, 2026 at 12:55 PM

331-348-6474 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: April 22, 2026 at 11:52 AM.

FTC report from Oro Valley, ARIZONA

April 22, 2026 at 12:30 PM

331-339-8421 was logged as a robocall. Violation date: April 21, 2026 at 1:56 PM.

FTC report from ILLINOIS

April 22, 2026 at 11:14 AM

331-788-8129 was logged as a robocall. Category: Dropped call or no message. Violation date: April 20, 2026 at 10:48 AM.

FTC report from ILLINOIS

April 22, 2026 at 11:12 AM

331-283-6183 was logged as a robocall. Category: Dropped call or no message. Violation date: April 20, 2026 at 3:54 PM.

FTC report from ILLINOIS

April 22, 2026 at 11:08 AM

331-283-6183 was logged as a robocall. Category: No Subject Provided. Violation date: April 21, 2026 at 12:09 PM.

FTC report from Bloomington, ILLINOIS

April 22, 2026 at 10:24 AM

331-296-5182 was logged as a live voice. Violation date: April 22, 2026 at 9:21 AM.

FTC report from Paradis, LOUISIANA

April 22, 2026 at 9:49 AM

331-248-9831 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: April 20, 2026 at 9:58 AM.