Area Code 510
California
Area code 510 serves California, primarily Oakland, in the Pacific Time (PT) time zone. It has served the region since 02-Sep-1991.
Overlay Area Code
This area code is part of an overlay region, meaning the same geographic area is served by multiple area codes. Overlay codes were introduced to meet growing demand for phone numbers without requiring existing customers to change their numbers.
This area code shares its geographic region with: area code 341 (Oakland).
In service since: 02-Sep-1991
Area Code Splits
Parts of this area code’s original geographic region were later assigned new area codes through splits. When a split occurs, some customers in the original area code region are assigned the new area code.
Split into: area code 925 (Concord).
Demographics
The estimated population served by area code 510 is approximately 1,809,235. The population density is 2,152 people per square mile, which is higher than the national average of 94. The median household income is $126,240, which is higher than the national median of $78,538. Approximately 50.6% of adults hold a bachelor's degree or higher, compared to the national rate of 35.0%. This rate is higher than the national average. The poverty rate stands at 9.1%, which is lower than the national rate of 12.4%.
History
Area code 510 was established in 1991 as a geographic area code. Over time, area code area code 925 was split from 510. It shares its territory with area code area code 341.
Demographics & Economics
- Total Population
- 1,809,235
- Population Density
- 2,152 people/sq miabove U.S. average (U.S.: 94 people/sq mi)
- Median Household Income
- $126,240above U.S. median (U.S.: $78,538)
- Poverty Rate
- 9.1%below U.S. average (U.S.: 12.4%)
- Unemployment Rate
- 5.3%near U.S. average (U.S.: 5.2%)
- Education Attainment
- Bachelor's Degree+50.6%above U.S. average (U.S.: 35.0%)High School or Lower22.3%
Statistics are population-weighted aggregations from Census ACS 5-year estimates.See Sources for details.
Geographic Coverage
State
CA
Major Cities
- Oakland
- Fremont
- Hayward
- Berkeley
- Richmond
- San Leandro
- Alameda
- Union City
- Castro Valley
- Newark
- San Pablo
- San Lorenzo
- Hercules
- El Cerrito
- Ashland
- Albany
- Pinole
- Cherryland
- Emeryville
- Piedmont
- Fairview
- Rodeo
- Kensington
- Tara Hills
and 11 more cities
Time Zone
- Pacific Time (PT)
Current Time
County Coverage
Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 510).
| County | Population | Share |
|---|---|---|
| Alameda, CA | 1,406,448 | 77.7% |
| Contra Costa, CA | 339,270 | 18.8% |
| San Francisco, CA | 63,517 | 3.5% |
Call Context
This area code covers a geographic region across CA, including Oakland and surrounding communities.
Nearby Area Codes
Area codes geographically closest to 510.
Other Area Codes in California
Area codes that also serve California, linked for easy comparison.
Frequently Asked Questions
Common questions about area code 510 and how phone numbering works.
Phone numbers assigned to area code 510 are tied to where they were originally provisioned — not the caller's current location. This code serving roughly 1809k people covers Oakland in CA, so a number originally set up there will retain the 510 prefix even if the owner moves or uses VoIP. As a densely populated metro area, Oakland sees high call volume from both local and redirected numbers. Mobile phones keep their original number when users relocate, and businesses often adopt local area codes to establish a regional presence.
Start by looking up the area code on this site to understand its geographic context — area code 510 is associated with Oakland in CA. For caller-specific details, use your carrier's caller ID features or check public directories. If you suspect fraud, you can report it to the FTC. To file a complaint about robocalls or spoofed numbers, visit the FCC Consumer Complaint Center. You can also register with the National Do Not Call Registry.
When an area's available number pool runs low, regulators introduce an "overlay" code covering the same territory. Both codes coexist, and new numbers are assigned from whichever has availability. Area code 510 serves the Oakland region in CA, where growing demand for phone numbers necessitated an additional code. This area code shares its region with area code 341. Learn more in our overlay vs split guide.