ZIP Code 21904 — Port Deposit, MD
21904 is a standard (street delivery) ZIP code serving Port Deposit, Maryland, in Cecil 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 21904 at a glance
| ZIP code | 21904 |
|---|---|
| Primary city | Port Deposit |
| State | Maryland (MD) |
| County | Cecil FIPS 24015 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 6,233 |
| Coordinates | 39.623030, -76.078120 |
How ZIP+4 works in 21904
The four digits after the hyphen encode a delivery segment inside 21904. 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 21904 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 21904.
| ZIP | City | Distance |
|---|---|---|
| 21917 | Colora, MD | 3.5 mi |
| 21903 | Perryville, MD | 3.9 mi |
| 21902 | Perry Point, MD | 5 mi |
| 21911 | Rising Sun, MD | 5 mi |
| 21078 | Havre De Grace, MD | 5.2 mi |
| 21914 | Charlestown, MD | 6.2 mi |
| 21918 | Conowingo, MD | 6.3 mi |
| 21901 | North East, MD | 6.9 mi |
| 21034 | Darlington, MD | 7.9 mi |
| 19362 | Nottingham, PA | 8.9 mi |
| 21028 | Churchville, MD | 9.5 mi |
| 21001 | Aberdeen, MD | 10.2 mi |
Questions about 21904
What is the ZIP+4 code for 21904?
21904 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 21904, you need to look up a specific street address to get them.
What city is 21904?
21904 is assigned to Port Deposit, Maryland, in Cecil 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.