| City: | Altadena, California |
| County: | Los Angeles County |
| Timezone: | Pacific (GMT -08:00) |
| Local Time: | 9:35:08 AM |
| Population: | No Population Data |
| Area Codes: | 323 / 626 / 738 |
| Classification: | PO Box |
| Coordinates: | 34.1897, -118.1303 |
| Quick Link: |
ZIP 91003 serves a specific location on Lake Avenue in Altadena, California, within Los Angeles County. This isn't a traditional community ZIP. It's a PO Box classification serving a single address with 113 delivery points, suggesting a large building or complex. The broader Altadena community receives regular street delivery through neighboring ZIP 91001.
The post office maintains 81 PO Boxes and handles delivery to 57 business addresses at this location. While classified as PO Box only, the ZIP does have one City carrier route serving Lake Avenue. This pattern is typical of large volume receivers or institutional sites that warrant their own ZIP code despite being geographically small.
Altadena sits in the foothills of the San Gabriel Mountains, just north of Pasadena. Residents and businesses in the wider Altadena area use ZIP 91001 for standard mail delivery. ZIP 91003 functions as a specialized postal designation rather than a community identifier.
Only Lake Avenue appears in delivery records, with secondary units indicating a multi-tenant facility.
ZIP Code 91003 supports both business and residential activity. According to the Business Census (2024), there are 4 business establishments, employing about 3 people with an annual payroll of $189,000.
| # Residential Mailboxes: | 0Source: USPS |
| # Business Mailboxes: | 0Source: USPS |
| Total Delivery Receptacles: | 92Source: USPS |
| Single Family Delivery Units: | 0Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 4Source: CBP |
| 1st Quarter Payroll: | $15,000Source: CBP |
| Annual Payroll: | $189,000Source: CBP |
| # of Employees: | 3Source: CBP |
ZIP Code 91003 is located in Los Angeles County, California, within the Los Angeles-Long Beach-Anaheim, CA Metropolitan Statistical Area (CBSA 31080) and California's 28th Congressional District. This Metro area has a population of 0 people, about 0.00% of whom live in ZIP Code 91003, and is subdivided into the Los Angeles-Long Beach-Glendale, CA division. It covers 0 sq mi of land and a water area of 0 sq mi.
| CBSA Name: | Los Angeles-Long Beach-Anaheim, CASource: Census |
| CBSA Number: | 31080Source: Census |
| CBSA Type: | MetroSource: Census |
| CBSA Division: | Los Angeles-Long Beach-Glendale, CA (CBSA Div 31084)Source: Census |
| CBSA Population: | 0Source: Census |
| MSA: | Los Angeles-Riverside-Orange County, CASource: Census |
| Land Area: | --Source: Census |
| Water Area: | --Source: Census |
| Congressional District: | 28Source: USPS |
| Congressional Land Area: | 218.45 sq miSource: Census |
| PMSA: | Los Angeles-Long Beach, CA PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | 0601290Source: Census |
| Place Name: | Altadena CDP; CaliforniaSource: Census |
We could not locate which school district 91003 belongs to, but we will update this once new district data is released. There are no public schools nor private schools with a mailing address in this ZIP Code. Listing Nearby schools instead. It also has 6 colleges, universities or post secondary education institutions nearby which would be a short commute to.
Our sources include trusted federal and licensed data from the United States Postal Service, U.S. Census Bureau, U.S. Geological Survey, Centers for Medicare & Medicaid Services, and the National Center for Education Statistics, along with proprietary datasets created by ZIP-Codes.com. Data last updated on February 1, 2026.