Where is area code 840?
NANPA assigns 840 to California. The source report does not provide city-level coverage for this record, so this page does not guess a particular city. Browse other codes in California
Verified area-code information
840 Area Code
840 is an in-service United States area code assigned to California. It identifies a numbering region, not a caller’s current location.
Official Numbering RegionVerified NANPA Assignment
CaliforniaArea Code 840
Country: United States•Time Zone: Pacific•Overlays: 909•In Service: 23-Feb-2021
- Numbering country
- United States
- Area-code type
- Geographic
- Numbering region
- California
- Time-zone information
- Pacific
- In service since
- 23-Feb-2021
View the official area-code maps ↗. Maps show numbering areas, not a caller’s location.
Time zones associated with 840
NANPA lists Pacific for this numbering area. These are numbering-region time zones, not a caller’s current location.
Pacific time
An area code can span more than one time zone. Local daylight-saving rules may differ.
What area codes overlay 840?
The NANPA source lists 909 in the same overlay complex. An overlay can serve the same broad numbering area; individual numbers still do not prove where a person is.
How do you dial a 840 number?
Use the North American country calling code +1 followed by the three-digit area code and seven-digit local number. For example, write the pattern as +1 840 XXX XXXX. Local dialing rules and charges depend on your location and provider. Check a supported dialing format or check NANPA’s 10-digit dialing list.
Assigned prefixes in 840
NANPA’s US report listed 120 assigned prefixes on 2026-09-29. These are code assignments, not a count of active phone numbers or proof of a caller’s current carrier. Search any US area code and prefix.
Top rate-center labels by assigned prefixes
| Rate center | Assigned prefixes |
|---|---|
| POMONA | 16 |
| ARROWHEAD | 14 |
| FONTANA | 12 |
| S BERNDINO | 12 |
| CHINO | 8 |
Top listed companies by assigned prefixes
| Assignment company | Assigned prefixes |
|---|---|
| T-MOBILE USA, INC. | 32 |
| FRACTEL, LLC | 26 |
| ONVOY, LLC - CA | 17 |
| NEW CINGULAR WIRELESS PCS, LLC | 16 |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CA | 12 |
840 prefix lookup
120 assigned prefixes are listed for this area code. Search NANPA’s US central-office code assignments. The listed company and rate center describe an assignment; number portability means they cannot identify the current carrier, subscriber, or caller.
The area-code file loads when you search. The three-digit prefix stays in your browser.
Check a number with area code 840
Enter the full ten-digit number to see its structure and formatting. The check stays in your browser.
Check a 840 number
Enter a 10-digit +1 North American number. We check its structure and area-code record, not the caller’s identity or whether the line is active.
Processed locally in your browser. Nothing you enter is sent to OfficialAreaCode or saved.
Received an unfamiliar call?
The displayed number may be spoofed. Do not rely on an area code as proof of caller identity. If the caller claims to represent a business, end the call and contact that business using a number you found independently.
Common questions about 840
What time zone is area code 840 in?
840 is assigned to California, and the NANPA record associates it with Pacific time. A phone number does not reveal its owner’s current time zone. The clock above uses a representative time zone for the numbering area.
Does 840 mean the caller is in California?
No. An area code is an assignment, and a person can travel, move, use internet calling, or display a spoofed number.
Can this page identify who called?
No. OfficialAreaCode has no live subscriber directory or spam-report database.