Area Code Detail

Area Code 331

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

IL
Reports, 30 Days 499

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

Reports, 180 Days 2,236

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 · 579 routing rows
  • T-MOBILE USA, INC. · 350 routing rows
  • NEW CINGULAR WIRELESS PCS, LLC - IL · 329 routing rows
  • CELLCO PARTNERSHIP DBA VERIZON WIRELESS - IL · 300 routing rows
  • BANDWIDTH.COM CLEC, LLC - IL · 178 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 · 53 routing rows
  • FRACTEL, LLC · 50 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 Richmond, TEXAS

October 31, 2026 at 4:55 PM

331-758-6510 was logged as a robocall. Violation date: October 31, 2026 at 3:52 PM.

FTC report

October 31, 2026 at 4:01 PM

331-600-0701 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 31, 2026 at 3:24 PM.

FTC report from CALIFORNIA

October 31, 2026 at 2:46 PM

331-529-9687 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 31, 2026 at 12:12 PM.

FTC report from Tuscaloosa, ALABAMA

October 31, 2026 at 1:16 PM

331-400-0508 was logged as a robocall. Violation date: October 31, 2026 at 11:11 AM.

FTC report from Montgomery, ILLINOIS

October 31, 2026 at 9:47 AM

331-229-9671 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: October 31, 2026 at 8:00 AM.

FTC report from Kingsport, TENNESSEE

October 31, 2026 at 8:12 AM

331-230-7581 was logged as a live voice. Violation date: October 31, 2026 at 8:05 AM.

FTC report from Mchenry, ILLINOIS

October 30, 2026 at 8:22 PM

331-267-8995 was logged as a live voice. Category: Dropped call or no message. Violation date: October 30, 2026 at 7:00 PM.

FTC report from ILLINOIS

October 30, 2026 at 2:37 PM

331-332-9775 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 3, 2026 at 7:00 PM.

FTC report from Homer Glen, ILLINOIS

October 30, 2026 at 12:24 PM

331-227-7319 was logged as a robocall. Category: Dropped call or no message. Violation date: October 30, 2026 at 2:45 PM.

FTC report from TEXAS

October 30, 2026 at 10:32 AM

331-529-9512 was logged as a robocall. Violation date: October 30, 2026 at 12:00 PM.

FTC report from NORTH CAROLINA

October 30, 2026 at 10:02 AM

331-600-0462 was logged as a robocall. Violation date: October 30, 2026 at 9:59 AM.

FTC report from Kingsport, TENNESSEE

October 29, 2026 at 11:39 PM

331-230-7581 was logged as a live voice. Violation date: October 29, 2026 at 10:00 PM.

FTC report from CALIFORNIA

October 29, 2026 at 8:02 PM

331-209-9854 was logged as a live voice. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 1, 2026 at 1:01 AM.

FTC report from ILLINOIS

October 29, 2026 at 6:25 PM

331-684-0001 was logged as a robocall. Violation date: September 28, 2026 at 2:23 PM.

FTC report from Cody, WYOMING

October 29, 2026 at 4:14 PM

331-248-9082 was logged as a robocall. Violation date: October 29, 2026 at 10:13 AM.

FTC report from Denver, COLORADO

October 29, 2026 at 4:14 PM

331-334-0079 was logged as a unwanted call. Violation date: October 28, 2026 at 3:19 PM.

FTC report from INDIANA

October 29, 2026 at 3:14 PM

331-336-4801 was logged as a robocall. Category: No Subject Provided. Violation date: October 28, 2026 at 12:56 PM.

FTC report from INDIANA

October 29, 2026 at 3:08 PM

331-336-4929 was logged as a robocall. Category: No Subject Provided. Violation date: October 29, 2026 at 12:04 PM.

FTC report from INDIANA

October 29, 2026 at 3:07 PM

331-336-4929 was logged as a robocall. Category: No Subject Provided. Violation date: October 29, 2026 at 4:04 PM.

FTC report from Plant City, FLORIDA

October 29, 2026 at 2:23 PM

331-899-9790 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 29, 2026 at 6:17 PM.

FTC report from Vacaville, CALIFORNIA

October 29, 2026 at 2:19 PM

331-310-1916 was logged as a robocall. Violation date: October 29, 2026 at 7:29 AM.

FTC report from ILLINOIS

October 29, 2026 at 12:01 PM

331-758-6516 was logged as a robocall. Category: Medical & prescriptions. Violation date: October 29, 2026 at 10:14 AM.

FTC report from Bakersfield, CALIFORNIA

October 29, 2026 at 11:31 AM

331-310-1962 was logged as a robocall. Violation date: October 29, 2026 at 8:11 AM.

FTC report from CALIFORNIA

October 29, 2026 at 10:56 AM

331-899-4532 was logged as a robocall. Violation date: October 28, 2026 at 6:40 PM.

FTC report from TEXAS

October 29, 2026 at 10:36 AM

331-800-4492 was logged as a robocall. Category: Warranties & protection plans. Violation date: October 29, 2026 at 9:00 AM.

FTC report from Aurora, ILLINOIS

October 29, 2026 at 6:48 AM

331-205-2630 was logged as a robocall. Violation date: October 21, 2026 at 8:31 AM.

FTC report from Aurora, ILLINOIS

October 29, 2026 at 6:30 AM

331-200-1043 was logged as a robocall. Violation date: October 27, 2026 at 8:30 AM.

FTC report from Summerville, SOUTH CAROLINA

October 28, 2026 at 7:02 PM

331-297-7521 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 28, 2026 at 12:52 PM.

FTC report from Woodbury, MINNESOTA

October 28, 2026 at 6:55 PM

331-334-0149 was logged as a robocall. Violation date: October 28, 2026 at 5:54 AM.

FTC report from NORTH CAROLINA

October 28, 2026 at 6:04 PM

331-356-6827 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 27, 2026 at 10:51 AM.

FTC report from Sanford, FLORIDA

October 28, 2026 at 4:33 PM

331-289-3786 was logged as a robocall. Violation date: October 28, 2026 at 4:27 PM.

FTC report from ILLINOIS

October 28, 2026 at 1:44 PM

331-296-6961 was logged as a unwanted call. Violation date: October 27, 2026 at 7:17 PM.

FTC report from Frankford, WEST VIRGINIA

October 28, 2026 at 1:40 PM

331-980-2110 was logged as a live voice. Violation date: October 28, 2026 at 1:30 PM.

FTC report from Westmont, ILLINOIS

October 28, 2026 at 12:49 PM

331-332-8315 was logged as a robocall. Category: Warranties & protection plans. Violation date: October 28, 2026 at 11:40 AM.

FTC report from ILLINOIS

October 28, 2026 at 11:58 AM

331-946-6535 was logged as a live voice. Violation date: October 28, 2026 at 9:35 AM.

FTC report from Plano, ILLINOIS

October 28, 2026 at 11:34 AM

331-217-7999 was logged as a robocall. Category: Reducing your debt (credit cards, mortgage, student loans). Violation date: October 28, 2026 at 12:00 AM.

FTC report from FLORIDA

October 28, 2026 at 7:40 AM

331-356-9839 was logged as a robocall. Violation date: October 27, 2026 at 7:45 AM.

FTC report from ILLINOIS

October 27, 2026 at 4:50 PM

331-771-6466 was logged as a robocall. Category: Calls pretending to be government, businesses, or family and friends. Violation date: October 27, 2026 at 12:00 PM.

FTC report from Ventura, CALIFORNIA

October 27, 2026 at 1:36 PM

331-215-9651 was logged as a robocall. Violation date: October 27, 2026 at 10:34 AM.

FTC report from ILLINOIS

October 27, 2026 at 1:16 PM

331-263-2764 was logged as a unwanted call. Category: No Subject Provided. Violation date: October 27, 2026 at 12:14 PM.