ZIP Code 21105 — Maryland Line, MD
21105 is a standard (street delivery) ZIP code serving Maryland Line, 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 21105 at a glance
| ZIP code | 21105 |
|---|---|
| Primary city | Maryland Line |
| State | Maryland (MD) |
| County | Baltimore FIPS 24005 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 36 |
| Coordinates | 39.715120, -76.652250 |
How ZIP+4 works in 21105
The four digits after the hyphen encode a delivery segment inside 21105. 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 21105 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 21105.
| ZIP | City | Distance |
|---|---|---|
| 17349 | New Freedom, PA | 3.1 mi |
| 21053 | Freeland, MD | 3.7 mi |
| 17361 | Shrewsbury, PA | 3.8 mi |
| 17355 | Railroad, PA | 3.9 mi |
| 21120 | Parkton, MD | 4.9 mi |
| 17363 | Stewartstown, PA | 5.1 mi |
| 21161 | White Hall, MD | 6 mi |
| 17327 | Glen Rock, PA | 7 mi |
| 17352 | New Park, PA | 8.7 mi |
| 17342 | Loganville, PA | 9.9 mi |
| 21111 | Monkton, MD | 10.3 mi |
| 21102 | Manchester, MD | 10.4 mi |
Questions about 21105
What is the ZIP+4 code for 21105?
21105 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 21105, you need to look up a specific street address to get them.
What city is 21105?
21105 is assigned to Maryland Line, 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.