ZIP Code 20634 — Great Mills, MD
20634 is a standard (street delivery) ZIP code serving Great Mills, Maryland, in St. Mary's 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 20634 at a glance
| ZIP code | 20634 |
|---|---|
| Primary city | Great Mills |
| State | Maryland (MD) |
| County | St. Mary's FIPS 24037 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 7,088 |
| Coordinates | 38.245820, -76.494120 |
How ZIP+4 works in 20634
The four digits after the hyphen encode a delivery segment inside 20634. 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 20634 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 20634.
| ZIP | City | Distance |
|---|---|---|
| 20620 | Callaway, MD | 1.8 mi |
| 20667 | Park Hall, MD | 3.3 mi |
| 20619 | California, MD | 3.6 mi |
| 20653 | Lexington Park, MD | 3.6 mi |
| 20692 | Valley Lee, MD | 4.4 mi |
| 20670 | Patuxent River, MD | 4.7 mi |
| 20686 | Saint Marys City, MD | 5.1 mi |
| 20630 | Drayden, MD | 5.6 mi |
| 20690 | Tall Timbers, MD | 6.2 mi |
| 20688 | Solomons, MD | 6.3 mi |
| 20629 | Dowell, MD | 6.9 mi |
| 20650 | Leonardtown, MD | 7.7 mi |
Questions about 20634
What is the ZIP+4 code for 20634?
20634 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 20634, you need to look up a specific street address to get them.
What city is 20634?
20634 is assigned to Great Mills, Maryland, in St. Mary's 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.