ZIP Code 91010 — Duarte, CA
91010 is a standard (street delivery) ZIP code serving Duarte, California, in Los Angeles County. To mail something here you only need these five digits — but the four-digit extension narrows delivery to a single point, and it is what USPS bulk postage discounts are priced on.
ZIP code 91010 at a glance
| ZIP code | 91010 |
|---|---|
| Primary city | Duarte |
| State | California (CA) |
| County | Los Angeles FIPS 06037 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Los_Angeles |
| Population | 27,589 |
| Coordinates | 34.141140, -117.959180 |
How ZIP+4 works in 91010
The four digits after the hyphen encode a delivery segment inside 91010. In practice one segment usually means:
- One side of one block — odd numbers on a street between two cross streets
- A single large building, or one floor of it
- A group of PO boxes, sometimes a single box
- A single business that receives enough mail to warrant its own code
That is why 91010 has no single ZIP+4: two neighbors across the street from each other usually have different ones. Enter a street address above and we will return the exact nine-digit code along with the standardized USPS address format.
Other ZIP codes in Duarte
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 91010.
| ZIP | City | Distance |
|---|---|---|
| 91008 | Duarte, CA | 1 mi |
| 91016 | Monrovia, CA | 2.5 mi |
| 91706 | Baldwin Park, CA | 3.1 mi |
| 91006 | Arcadia, CA | 3.9 mi |
| 91722 | Covina, CA | 4.3 mi |
| 91790 | West Covina, CA | 5.2 mi |
| 91007 | Arcadia, CA | 5.2 mi |
| 91024 | Sierra Madre, CA | 5.4 mi |
| 91723 | Covina, CA | 5.7 mi |
| 91732 | El Monte, CA | 5.7 mi |
| 91740 | Glendora, CA | 6.2 mi |
| 91780 | Temple City, CA | 6.2 mi |
Questions about 91010
What is the ZIP+4 code for 91010?
91010 is the five-digit ZIP code. The ZIP+4 adds four more digits that identify a specific delivery point — usually one side of a city block, a single building, or a group of PO boxes. Because those four digits change from address to address within 91010, you need to look up a specific street address to get them.
What city is 91010?
91010 is assigned to Duarte, California, in Los Angeles County.
Do I need to use the ZIP+4?
It is optional for ordinary mail, but it speeds up sorting and it is required for most USPS bulk-mail postage discounts. Many address-verification and e-commerce systems also use ZIP+4 to confirm a delivery point exists.
Need thousands of these?
Upload a CSV and get ZIP+4, county, carrier route, and delivery-point data appended to every row — or call the API directly.