ZIP Code 91016 — Monrovia, CA
91016 is a standard (street delivery) ZIP code serving Monrovia, 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 91016 at a glance
| ZIP code | 91016 |
|---|---|
| Primary city | Monrovia |
| State | California (CA) |
| County | Los Angeles FIPS 06037 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Los_Angeles |
| Population | 41,140 |
| Coordinates | 34.152460, -118.000650 |
How ZIP+4 works in 91016
The four digits after the hyphen encode a delivery segment inside 91016. 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 91016 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.
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 91016.
| ZIP | City | Distance |
|---|---|---|
| 91008 | Duarte, CA | 1.8 mi |
| 91006 | Arcadia, CA | 1.9 mi |
| 91010 | Duarte, CA | 2.5 mi |
| 91024 | Sierra Madre, CA | 2.9 mi |
| 91007 | Arcadia, CA | 3.2 mi |
| 91706 | Baldwin Park, CA | 4.3 mi |
| 91780 | Temple City, CA | 4.7 mi |
| 91107 | Pasadena, CA | 4.9 mi |
| 91731 | El Monte, CA | 5.5 mi |
| 91732 | El Monte, CA | 5.6 mi |
| 91775 | San Gabriel, CA | 5.7 mi |
| 91722 | Covina, CA | 6.6 mi |
Questions about 91016
What is the ZIP+4 code for 91016?
91016 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 91016, you need to look up a specific street address to get them.
What city is 91016?
91016 is assigned to Monrovia, 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.