--- title: "Area code 341: California, United States" url: "https://lookvalid.com/area-code/341.md" canonical_url: "https://lookvalid.com/area-code/341" last_updated: "2026-10-23" type: "reference" summary: "Area code 341 serves California, United States. Number formats, numbering rules, a live phone validator and the other codes in California." --- # Area code 341: California, United States Area code 341 serves California, United States. Number formats, numbering rules, a live phone validator and the other codes in California. NANPA lists 108 central office codes (prefixes) in use in area code 341, held by 16 holders across 13 rate centers. Fractel holds the most prefixes, 33 (31%). 99% of the prefixes are pooled, which means their thousands-blocks can belong to different companies. The FCC unwanted-call data has 198 complaints on file for 179 numbers in 341, most often filed as "Unwanted Calls". These are consumer reports, not findings. ## Facts - In service since: 2019-07-22 - Time zone: Pacific (P) - Assigned overlays: 510 (1991-09-02) - Prefixes in use: 108 - Pooled prefixes: 107 (99%) - Rate centers: 13 - Companies holding prefixes: 16 - Assignment dates on file: 2019-05-31 to 2026-07-28 (107 prefixes) - ZIP codes in its places: 15 ## Rate centers | Rate center | Prefixes | Share | | --- | --- | --- | | FRNK MAIN | 15 | 14% | | HAYWARD | 12 | 11% | | OKLD BKLY | 11 | 10% | | OKLD FRTVL | 10 | 9% | | RICHMOND | 10 | 9% | | ELSBR-PINL | 9 | 8% | | FRNK GRNLF | 8 | 7% | | FRNK OLIVR | 8 | 7% | | 5 other rate centers | 25 | 23% | ## Carriers | Holder | Prefixes | Share | | --- | --- | --- | | Fractel | 33 | 31% | | Onvoy | 21 | 19% | | T-Mobile USA | 12 | 11% | | New Cingular Wireless PCS | 11 | 10% | | Bandwidth.com CLEC | 8 | 7% | | Sonic Telecom | 4 | 4% | | 10 other carriers | 19 | 18% | A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company. ## History - 1991-09-02: Area code 510, named as the parent of 341 in the NANPA report, was in service. - 2019-07-22: Area code 341 went into service. ## Nearest area codes The area codes closest to 341, measured between the centers of the ZIP code places they serve, are 925 (about 13 miles), 415 (about 25 miles), 628 (about 25 miles), 650 (about 25 miles) and 669 (about 43 miles). ## ZIP codes 15 ZIP codes fall in places that have a rate center in this area code. The places with the most are Hayward, CA (7 ZIP codes), Richmond, CA (7 ZIP codes) and Crockett, CA (1 ZIP code). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes. ## Complaints on file 198 complaints for 179 numbers. Numbers whose latest complaint falls in each year: - 2023: 25 - 2024: 27 - 2025: 42 ## Questions ### Where is area code 341? NANPA assigns area code 341 to California, United States. ### In which state does area code 341 sit? California. 341 is one of 41 area codes the NANPA table assigns to the state. ### Which places does area code 341 cover? The places with the most ZIP codes among the rate centers in 341 are Hayward, CA, Richmond, CA and Crockett, CA. The rate center list on this page shows all of them. ### Who owns area code 341? NANPA assigns area codes. Within 341, Fractel holds the most prefixes, 33 prefixes or 31%. ### Which time zone does 341 use? The NANPA NPA report lists the time zone for 341 as Pacific (P). ### What year did 341 enter service? The NANPA NPA report gives an in-service date of 2019-07-22, so 341 has been in use since 2019. ### Does area code 341 have an overlay? Yes. 510 (in service 1991-09-02) shares the same area with 341, so numbers from all of them are local to each other. ### Which area codes are nearest to 341? The area codes closest to 341, measured between the centers of the ZIP code places they serve, are 925 (about 13 miles), 415 (about 25 miles), 628 (about 25 miles), 650 (about 25 miles) and 669 (about 43 miles). ### How many prefixes does area code 341 have? NANPA's report dated 2026-10-17 lists 108 prefixes in service in 341, spread over 13 rate centers and 16 holders. ### Are there complaints about 341 numbers? The FCC data on file has 198 complaints for 179 numbers in 341. They are unverified consumer reports. A number with no complaints on file is not proven safe. Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).