ZIP Code 21131 — Phoenix, MD
21131 is a standard (street delivery) ZIP code serving Phoenix, Maryland, in Baltimore 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 21131 at a glance
| ZIP code | 21131 |
|---|---|
| Primary city | Phoenix |
| State | Maryland (MD) |
| County | Baltimore FIPS 24005 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 7,141 |
| Coordinates | 39.503380, -76.574860 |
How ZIP+4 works in 21131
The four digits after the hyphen encode a delivery segment inside 21131. 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 21131 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 21131.
| ZIP | City | Distance |
|---|---|---|
| 21013 | Baldwin, MD | 4.5 mi |
| 21031 | Hunt Valley, MD | 4.6 mi |
| 21030 | Cockeysville, MD | 4.9 mi |
| 21111 | Monkton, MD | 5 mi |
| 21057 | Glen Arm, MD | 5.1 mi |
| 21093 | Lutherville Timonium, MD | 5.8 mi |
| 21082 | Hydes, MD | 5.9 mi |
| 21286 | Towson, MD | 6.2 mi |
| 21152 | Sparks Glencoe, MD | 6.5 mi |
| 21051 | Fork, MD | 6.8 mi |
| 21204 | Towson, MD | 7.5 mi |
| 21047 | Fallston, MD | 7.5 mi |
Questions about 21131
What is the ZIP+4 code for 21131?
21131 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 21131, you need to look up a specific street address to get them.
What city is 21131?
21131 is assigned to Phoenix, Maryland, in Baltimore 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.