Altadena, CA ZIP Codes
Altadena, California has 2 ZIP codes: for street addresses and for PO boxes.
Mail addressed to Altadena covers nearby places too.
Where the 91001 ZIP code reaches
Tap or point to an area to see its ZIP code.Full-size map
91003 has no area on the map: it is a PO box or single-organization ZIP code. Dashed line: the Altadena Census outline.
Map: Census Bureau ZIP Code Tabulation Areas (2020) and place limits (2024).
Check an address in Altadena
Street ranges from the Census Bureau, 2026. PO box and organization ZIP codes are not found by street. A new street may be missing: address not found?
Altadena PO box and business ZIP codes
| ZIP | Type and post office or station |
|---|---|
| 91001 | street delivery Altadena Carriers |
| 91003 | PO boxes at the Altadena Carriers post office Altadena Carriers |
ZIP codes from nearby towns that reach into Altadena
- 91104, mailing town Pasadena, covers 8 percent of Altadena
Why your mail may say Altadena when you live outside it
A letter addressed to Altadena can go to a home outside the town, because ZIP areas follow delivery routes, not town lines.
The reverse happens too: parts of Altadena use 91104, which mails under a neighboring town's name.
A ZIP code does not set your city, school district or tax. Los Angeles County property records show which city you are in.
Altadena ZIP code questions
What is the main ZIP code for Altadena?
91001, the ZIP code of the main Altadena Carriers post office at 600 Lincoln Ave.
Which Altadena ZIP codes are for PO boxes only?
91003. Mail to it goes to boxes at the post office, not to street addresses.
What county is Altadena in?
Los Angeles County.
ZIP codes for towns near Altadena
More towns near Altadena: Monrovia, Rosemead, Monterey Park, El Monte, Burbank, East Los Angeles, Baldwin Park, Montebello, Azusa.
Sources and last checked
USPS ZIP Locale Detail (October 1, 2026), GeoNames (CC BY 4.0), U.S. Census Bureau, HUD-USPS crosswalk.
Checked October 20, 2026. Sources · How we build our lists · Corrections