Postal reference / United States
91001Altadena, California
ZIP code 91001 is a United States postal code for Altadena, California. Its county association is Los Angeles County. The map reference point is at 34.1912, -118.1392.
- State / territory
- California
- Recorded place name
- Altadena
- County association
- Los Angeles
- Estimated coordinate
- 34.1912, -118.1392
View on OpenStreetMap - ZIP prefix
- 910 · 25 ZIP codes share it
- Data source
- GeoNames postal reference, snapshot September 26, 2026
GeoNames reference data. County associations may not include every intersecting county, place names are postal names rather than legal boundaries, and coordinates are approximate. This is not address validation.
Area
- Land area
- 8.26 sq mi (2023 Census Gazetteer)
Figures are for the ZIP Code Tabulation Area (ZCTA) that most closely matches this ZIP code, not an exact match to USPS delivery boundaries. Source: U.S. Census Bureau, 2023 Gazetteer + 2023 ACS 5-Year Estimates, retrieved 2026-09-27. How to read this data.
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California directoryOther ZIP codes in Altadena, CA
Altadena has 2 ZIP codes in the reference dataset.
- 91003Los Angeles
Nearby ZIP code reference points
| ZIP code | Place | State | County association | Miles |
|---|---|---|---|---|
| 91003 | Altadena | CA | Los Angeles | 0.5 |
| 91104 | Pasadena | CA | Los Angeles | 1.8 |
| 91103 | Pasadena | CA | Los Angeles | 1.9 |
| 91012 | La Canada Flintridge | CA | Los Angeles | 2.8 |
| 91199 | Pasadena | CA | Los Angeles | 3.0 |
| 91102 | Pasadena | CA | Los Angeles | 3.0 |
| 91109 | Pasadena | CA | Los Angeles | 3.0 |
| 91110 | Pasadena | CA | Los Angeles | 3.0 |
Straight-line distance between reference points. Nearby points do not prove that ZIP areas touch.
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