840 area code
Area code 840 is in California. It covers San Bernardino, Fontana, Ontario and 30 other places: 64 ZIP codes in San Bernardino, Los Angeles, Riverside and 1 other county. Local time there is , Pacific Time. In service since 2021 as an overlay: it covers the same area as 909, so a number from there can have either code.
- State
- California
- Time zone
- Pacific
- Largest city
- Fontana
- Overlays
- 909
- In service since
- 2021
- Rate centres
- 19
- Prefixes assigned
- 128 (1,280,000 numbers)
Who calls from a 840 number
NANPA records the carrier each block of 840 numbers is assigned to. Of the 1.2 million 840 numbers assigned, 59% are with mobile carriers (AT&T Mobility, T-Mobile and Verizon Wireless); 41% with cable, internet-calling, business and other carriers (Onvoy, Commio and Bandwidth).
That is who the numbers were assigned to: people keep their number when they change carrier, so any one number may have moved since.
| Carrier | Kind | Share |
|---|---|---|
| Onvoy | Cable, VoIP, other | 24% |
| AT&T Mobility | Mobile | 23% |
| T-Mobile | Mobile | 20% |
| Verizon Wireless | Mobile | 15% |
| Commio | Cable, VoIP, other | 5% |
| Bandwidth | Cable, VoIP, other | 3% |
An area code says where a number was issued, not where the caller is: people keep their numbers when they move, and caller ID can be set to show any number, which the FCC calls spoofing. If a call you did not expect asks for money or personal details, the FCC advises hanging up and calling the company back on a number you look up yourself. Unwanted calls can be reported to the FTC at ReportFraud.ftc.gov.
Places in area code 840
The 16 places with a telephone rate centre of their own using 840, largest first. Each links to its ZIP codes.
| Place | ZIP codes | Population |
|---|---|---|
| San Bernardino, CA | 15 | 222,724 |
| Fontana, CA | 5 | 214,169 |
| Ontario, CA | 4 | 180,547 |
| Pomona, CA | 4 | 147,943 |
| Rialto, CA | 2 | 104,143 |
| Chino, CA | 2 | 92,652 |
| Upland, CA | 3 | 79,257 |
| Redlands, CA | 3 | 73,375 |
| Highland, CA | 1 | 56,675 |
| Colton, CA | 1 | 53,772 |
| Diamond Bar, CA | 1 | 53,355 |
| Claremont, CA | 1 | 36,595 |
| Big Bear City, CA | 1 | 11,431 |
| Calimesa, CA | 1 | 10,902 |
| Crestline, CA | 1 | 9,835 |
| Mentone, CA | 1 | 9,514 |
Nearby places using 840
These places have no rate centre of their own in NANPA's records; the nearest one uses 840. Near an area-code boundary that can be wrong for part of a town.
- Rancho Cucamonga
- Yucaipa
- Montclair
- La Verne
- Muscoy
- Lake Arrowhead
- San Antonio Heights
- Patton
- Twin Peaks
- Sugarloaf
- Blue Jay
- Cedarpines Park
- Lytle Creek
- Oak Glen
- Rimforest
- Skyforest
- Guasti
ZIP codes in area code 840
64 ZIP codes in 30 towns, by the town each is mailed to, largest first. Each links to its own page.
Where 840 numbers are issued
NANPA's rate centres with the most 840 prefixes (each prefix is 10,000 numbers), under NANPA's own abbreviated names.
| Rate centre | Place | Prefixes |
|---|---|---|
POMONA | Pomona | 16 |
S BERNDINO | San Bernardino | 15 |
ARROWHEAD | — | 14 |
FONTANA | Fontana | 12 |
CHINO | Chino | 8 |
CLAREMONT | Claremont | 8 |
Counties
The counties of its ZIP codes, most residents first, with how many of its ZIP codes each has.
Which code covers where you are now? What area code am I in? answers from your location.
Questions about area code 840
Where is area code 840?
Area code 840 is in California. It covers San Bernardino, Fontana, Ontario and 30 other places: 64 ZIP codes in San Bernardino, Los Angeles, Riverside and 1 other county.
What ZIP codes are in area code 840?
64 ZIP codes, by the town each is mailed to: San Bernardino (15, 92401 to 92427), Fontana (5, 92331 to 92337), Ontario (4, 91758 to 91764), Rancho Cucamonga (5, 91701 to 91739) and 26 more towns. The full list is on this page.
What time zone is area code 840 in?
Pacific time.
Is a 840 number a mobile or a landline?
It can be either. 59% of 840 numbers are assigned to mobile carriers and 0% to local phone companies (NANPA, 2026-10-10); the rest are with cable, internet-calling, business and paging carriers. A number keeps its area code when it moves to another carrier.
What area codes overlay 840?
909. They cover the same area as 840, so a new number there can be given any of them.
Does a 840 number mean the caller is in California?
Not necessarily. An area code says where the number was first issued. People keep their numbers when they move or switch carriers, and calling software can show any number, so a 840 call can come from anywhere.
Other area codes in California
- 209 Fresno
- 213 Los Angeles
- 279 Sacramento
- 310 Torrance
- 323 Los Angeles
- 341 Oakland
- 350 Stockton
- 357 Fresno
- 369 Santa Rosa
- 408 San Jose
- 415 San Francisco
- 424 Torrance
- 442 Oceanside
- 510 Oakland
- 530 Chico
- 559 Fresno
- 562 Long Beach
- 619 San Diego
- 626 Pasadena
- 628 San Francisco
- 650 San Mateo
- 657 Anaheim
- 661 Bakersfield
- 669 San Jose
- 707 Santa Rosa
- 714 Anaheim
- 738 Los Angeles
- 747 Glendale
- 760 Oceanside
- 805 Bakersfield
- 818 Glendale
- 820 Oxnard
- 831 Salinas
- 837 Chico
- 858 San Diego
- 909 Fontana
- 916 Sacramento
- 925 Concord
- 949 Irvine
- 951 Riverside
All 41 California area codes, by area, with the cities each covers
Source: NANPA NPA database, central office code and thousands-block assignments, 2026-10-10. Places are matched to NANPA's rate centres by name; see sources.
Cite this page
zipcodes.pro. “Area code 840.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/area-code/840
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