840 Area Code — California
840 is a North American Numbering Plan area code for California, the United States. It covers about 1,860,036 people in 36 towns and 72 ZIP codes, including San Bernardino, Fontana and Ontario.
| Field | Value |
|---|---|
| Area code | 840 |
| Country | United States (+1) |
| State / province | California |
| Type | Shares its towns with 909 |
| Time zone | Pacific |
| Population covered | 1,860,036 |
| Towns covered | 36 |
| ZIP codes | 72 |
| Approx. centre | 34.121, -117.397 |
Where area code 840 is used
Area code 840 is assigned to California, the United States, inside the North American Numbering Plan. Numbers in the code are written (840) NXX-XXXX at home and +1 840 NXX-XXXX when dialled from outside Canada and the United States. Since the NANP moved to 10-digit dialling you must always include the area code, even for a local call.
Other area codes in this footprint: 909. They serve towns in the same territory, so a single street can contain numbers from more than one code. That is normal in the NANP and does not change how you dial.
Towns and cities in area code 840
The 36 towns below are the largest in the 840 footprint, ranked by population. Every one of them links to its own page with the full list of area codes and ZIP codes for that town.
| Town | County | Population | ZIP codes |
|---|---|---|---|
| San Bernardino | San Bernardino County | 257,273 | 15 |
| Fontana | San Bernardino County | 239,054 | 5 |
| Ontario | San Bernardino County | 183,440 | 4 |
| Rancho Cucamonga | San Bernardino County | 175,531 | 5 |
| Pomona | Los Angeles County | 152,679 | 4 |
| Rialto | San Bernardino County | 105,208 | 2 |
| Chino | San Bernardino County | 97,967 | 2 |
| Upland | San Bernardino County | 82,715 | 3 |
| Redlands | San Bernardino County | 80,519 | 3 |
| Colton | San Bernardino County | 57,365 | 1 |
| Highland | San Bernardino County | 56,179 | 1 |
| Yucaipa | San Bernardino County | 55,366 | 1 |
Counties covered
| County | ZIP codes |
|---|---|
| San Bernardino County | 62 |
| Los Angeles County | 8 |
| Riverside County | 1 |
| Imperial County | 1 |
Other area codes serving the same towns
Nearby area codes
How to dial area code 840
- Within North America: 840 + 7-digit number (840-NXX-XXXX). The leading 1 is optional on a mobile phone and required on most landlines for long-distance.
- From abroad: your country's international prefix, then 1, then 840, then the 7-digit number — for example 00 1 840 NXX-XXXX from most of Europe.
Frequently asked questions
What area code is 840?
840 is a North American Numbering Plan area code assigned to California, the United States. It covers about 1,860,036 people in 36 towns.
Is 840 a US or Canadian area code?
840 is a United States area code. Canada and the United States share the +1 country code, so both are part of the same numbering plan.
What time zone is area code 840 in?
Area code 840 is in the Pacific time zone.
Do I have to dial 10 digits?
Yes. Every NANP call now requires the area code plus the seven-digit number, even for a local call.