Area code 840: where it is and who calls from it
Area code 840 is in California.
California (southwestern San Bernardino County and a small portion of Los Angeles and Riverside counties, including Fontana, Pomona, Chino Hills, Claremont, Chino, Ontario, and Redlands)
| Where | California |
|---|---|
| Time zone | Pacific Time ยท local time |
| In service since | 2021 |
| Overlay | Yes, with 909 |
| Prefixes assigned | 128 of 792 possible (16%) |
Overlay: 840 covers the same area as 909. Overlay areas use 10-digit dialing, so a seven-digit number alone won't connect, and neighbors can have different area codes.
Where 840 numbers started
Every prefix is assigned to a rate center, the local calling area it was set up in. These are the biggest in 840, with how many prefixes each has.
Who holds 840 numbers
- Mobile carrier 50%
- Internet / business phone carrier 50%
| Carrier | Type | Prefixes | Share |
|---|---|---|---|
| T-Mobile (including Sprint) | Mobile carrier | 32 | 25% |
| Fractel | Internet / business phone carrier | 26 | 20% |
| Onvoy | Internet / business phone carrier | 25 | 20% |
| AT&T Mobility | Mobile carrier | 18 | 14% |
| Verizon Wireless | Mobile carrier | 13 | 10% |
| Bandwidth | Internet / business phone carrier | 4 | 3% |
| Terra Nova Telecom | Internet / business phone carrier | 3 | 2% |
| TON80 Communications | Internet / business phone carrier | 2 | 2% |
| Hd Carrier | Internet / business phone carrier | 1 | <1% |
| Boost / Virgin Mobile | Mobile carrier | 1 | <1% |
Most prefixes are pooled: the 10,000 numbers in each are handed out in blocks of 1,000 to different carriers, and people can also take their numbers to another carrier. So the carrier shown is where the prefix started, not a guarantee about any one number.
States served: California.
Other area codes in California
209 213 279 310 323 341 350 357 369 408 415 424 442 510 530 559 562 619 626 628 650 657 661 669 707 714 738 747 760 805 818 820 831 837 858 909 916 925 949 951
Got a call from 840?
An area code tells you where a number was first assigned, not where the caller is. People keep their numbers when they move, and scammers can fake any number. If you weren't expecting the call, let it go to voicemail.
If the call shows a 840 number that matches the first six digits of your own, that's often neighbor spoofing. Use the box above to check the full number.
Area code facts from the NANPA area code database (updated 10/06/2026); prefixes and carriers from NANPA's central office code records (updated 2026-10-10). Place description adapted from Wikipedia, CC BY-SA 4.0.