Area Code 331 – Zip Codes, Time Zone & Aurora Map

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📞 331 Area Code — Quick Reference
📍 LocationAurora, Illinois
🕐 Time ZoneCentral (UTC-6/UTC-5)
🗓️ StatusActive — Geographic

Area code 331 serves Aurora and surrounding communities in Illinois. Whether you received an unexpected call from this number or you’re trying to figure out where a 331 number is based, this guide covers the exact location, time zone, spam reputation, blocking instructions, and which cities fall under this code.

📍 Where Is the 331 Area Code Located?

The 331 area code is located in Illinois, primarily serving Aurora and the surrounding region. It’s a standard geographic area code under the North American Numbering Plan (NANP). Keep in mind that mobile number portability means someone could carry a 331 number with them after moving — so the code tells you where the number was issued, not necessarily where the person is right now.

331 Area Code — Location Details
State/ProvinceIllinois (IL)
Major CityAurora
CountryUnited States (+1)
Time ZoneCentral (UTC-6/UTC-5)
TypeGeographic — Standard
NANPA StatusActive

🕐 331 Area Code Time Zone

The 331 area code operates in the Central Time Zone (UTC-6/UTC-5). Here’s how it compares to other US time zones:

Time ZoneDifference from 331
Eastern Time+1 hour
Central TimeSame time
Mountain Time-1 hour
Pacific Time-2 hours
💡 Calling Tip: Reach someone in the 331 area between 10 AM – 4 PM their local time for the best chance of an answer. Calls outside those hours are more likely to be screened or ignored.

🛡️ Is 331 Area Code Spam or Scam?

Is a 331 call spam? Not necessarily — 331 is a legitimate area code serving Aurora and surrounding areas. That said, scammers routinely spoof 331 numbers to make their calls look local. The general rule: if you don’t recognize the number and they don’t leave a voicemail, it’s probably junk.

⚠️ Red Flag: If a 331 caller demands immediate payment via gift cards, wire transfer, or crypto — hang up. No legitimate organization uses these methods. Verify by calling the company’s official number directly.

How to verify: Don’t call back the number — look up the official number for whatever organization the caller claimed to represent and call that instead. Google the full 10-digit number in quotes to check if others have reported it as spam.

📵 How to Block 331 Spam Calls & Texts

Block on iPhone

  1. Open Phone → tap Recents
  2. Tap ⓘ next to the 331 spam number
  3. Scroll down → “Block this Caller”
  4. Silence all unknowns: Settings → Phone → Silence Unknown Callers → ON

Block on Android

  1. Open Phone → find the 331 number
  2. Tap ⋮ menu → “Block number”
  3. For broader blocking: Settings → Blocked numbers → Unknown toggle ON

Report Spam

  1. Forward spam texts to 7726 (SPAM)
  2. Report at reportfraud.ftc.gov
  3. Register at donotcall.gov or call 1-888-382-1222

🔍 Who Called from 331? Reverse Lookup

  1. Google the full 10-digit number in quotes — catches ~70% of unknown callers
  2. Check Whitepages.com or Truecaller.com
  3. Search 800notes.com for community reports
  4. No voicemail left? Almost certainly spam — legitimate callers leave messages
⚠️ One-Ring Scam: If a 331 number rings once and hangs up, do NOT call back. This scam connects you to a premium-rate line that charges your bill.

🔗 Nearby Area Codes

CodeLocationTime Zone
773Chicago, IllinoisCentral
312Chicago, IllinoisCentral
630Aurora, IllinoisCentral
224Arlington Heights, IllinoisCentral
217Springfield, IllinoisCentral

❓ 331 Area Code — FAQ

What state is 331 area code in?
The 331 area code is in Illinois, serving Aurora and surrounding areas.
What city does 331 cover?
331 primarily covers Aurora and nearby communities in Illinois.
Is 331 toll-free?
No. 331 is a geographic area code. Toll-free codes are 800, 833, 844, 855, 866, 877, 888.
What time zone is 331?
Central (UTC-6/UTC-5).
Is 331 a scam?
331 is legitimate — it serves real people in Aurora. But scammers may spoof 331 numbers. Verify suspicious callers independently.
Why do I keep getting 331 calls?
Repeated 331 calls without a known contact are likely robocalls. Use your phone’s Silence Unknown Callers feature.
Can I get a 331 number remotely?
Yes — VoIP services like Google Voice offer 331 numbers regardless of where you live.
Is 331 cell or landline?
331 covers both. US area codes don’t distinguish between mobile and landline.
How do I block 331 calls?
iPhone: Settings → Phone → Silence Unknown Callers. Android: Phone → Settings → Blocked numbers. For area-code blocking, use Truecaller or RoboKiller.

🔗 Related Area Code Guides

Updated April 2026 · Data from NANPA & FCC · areacodess.org/