ZIP Code 21640 — Henderson, MD
21640 is a standard (street delivery) ZIP code serving Henderson, Maryland, in Caroline 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 21640 at a glance
| ZIP code | 21640 |
|---|---|
| Primary city | Henderson |
| State | Maryland (MD) |
| County | Caroline FIPS 24011 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 1,163 |
| Coordinates | 39.070360, -75.825330 |
How ZIP+4 works in 21640
The four digits after the hyphen encode a delivery segment inside 21640. 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 21640 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 21640.
| ZIP | City | Distance |
|---|---|---|
| 21636 | Goldsboro, MD | 3.4 mi |
| 21644 | Ingleside, MD | 4.2 mi |
| 21607 | Barclay, MD | 4.7 mi |
| 21649 | Marydel, MD | 5.3 mi |
| 19964 | Marydel, DE | 5.7 mi |
| 21639 | Greensboro, MD | 7.5 mi |
| 21623 | Church Hill, MD | 8.1 mi |
| 21668 | Sudlersville, MD | 8.3 mi |
| 21660 | Ridgely, MD | 8.6 mi |
| 19953 | Hartly, DE | 8.9 mi |
| 19934 | Camden Wyoming, DE | 10.4 mi |
| 21617 | Centreville, MD | 11.5 mi |
Questions about 21640
What is the ZIP+4 code for 21640?
21640 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 21640, you need to look up a specific street address to get them.
What city is 21640?
21640 is assigned to Henderson, Maryland, in Caroline 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.