Illinois · Phone number directory

331 phone numbers & call reports

Received a call from a number starting with 331? Browse available reports below or look up the full number to check its complaint history.

Numbers with reports: 340
FTC complaints: 640
WhoseNum community reports: 0

Reports describe individual experiences, not a verdict on every 331 number. About our sources

Area code guide

331: Illinois

Area code 331 is a geographic telephone code assigned to Illinois. NANPA records its introduction on Oct 7, 2007. Its recorded overlay relationships connect it with 630. Overlay codes share all or part of a numbering region.

State / territory: Illinois
In service since: Oct 7, 2007
Predominant time zone: Central
Local dialing within 331: 1 + 10 digits
Active overlay partners: 630

Time zones and dialing patterns describe the numbering region. They do not establish a caller’s current time or location. Carrier dialing options can differ.

Rate centers in the 331 assignment data (24)

These are telephone rate-center labels from NANPA’s block assignments, not a list of every city or an exact coverage boundary.

Aurora
Bartlett
Batavia
Big Rock
Downersgrv
Elburn
Elmhurst
Geneva
Glen Ellyn
Hinsdale
Itasca
Kaneville
Lemont
Lombard
Naperville
Oswego
Plano
Roselle
St Charles
Sugargrove
W Chicago
Warrenvl
Wheaton
Yorkville

Sources & retrieval dates

NANPA thousands-block assignments Retrieved Oct 18, 2026
NANPA area-code database field definitions Retrieved Oct 19, 2026
NANPA area-code database Retrieved Oct 19, 2026

Numbering facts are stored from the cited sources and updated when a new snapshot is imported. Regional context is separate from unverified call reports.

331 numbers with reports

Open a number to see its available reports and sources.

340 numbers

Ordered by available report and complaint counts. “Record updated” reflects a data update, not necessarily the date of a call.

Browse 331 phone prefixes

Explore exchanges with available reports in this area code.

Questions about 331 numbers

Where are 331 phone numbers from?

The 331 area code is associated with Illinois. This numbering information does not establish where a caller is currently located. Caller ID can be spoofed.

Is every call from 331 spam?

No. A shared prefix does not mean that the numbers belong to the same caller or that every call is unwanted. Reports and complaints are unverified. Check the full number and the details of the call before drawing a conclusion.

What if the number that called me is not listed?

This directory shows numbers with published WhoseNum reports or complaints in our available FTC snapshot. It is not a complete list of assigned numbers or all past calls. Use the lookup above to check an unlisted number and share your own experience from its number page.

What these reports cover

FTC counts come from our imported Do Not Call complaint snapshot, covering complaint filing dates from Sep 10, 2026 to Oct 15, 2026. This is a partial snapshot, not the FTC’s full complaint history. WhoseNum community counts include published reports submitted directly to this site. Neither source verifies who placed a call. Read the source and coverage notes.

331 phone numbers & call reports

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331: Illinois

331 numbers with reports

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Available reports at a glance

331: Illinois

Browse 331 phone prefixes

Questions about 331 numbers

What these reports cover