ZIP Code 21405 — Annapolis, MD
21405 is a standard (street delivery) ZIP code serving Annapolis, Maryland, in Anne Arundel 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 21405 at a glance
| ZIP code | 21405 |
|---|---|
| Primary city | Annapolis |
| State | Maryland (MD) |
| County | Anne Arundel FIPS 24003 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 495 |
| Coordinates | 39.029960, -76.549710 |
How ZIP+4 works in 21405
The four digits after the hyphen encode a delivery segment inside 21405. 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 21405 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.
Other ZIP codes in Annapolis
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 21405.
| ZIP | City | Distance |
|---|---|---|
| 21401 | Annapolis, MD | 2.8 mi |
| 21032 | Crownsville, MD | 2.9 mi |
| 21012 | Arnold, MD | 3 mi |
| 21146 | Severna Park, MD | 3.3 mi |
| 21402 | Annapolis, MD | 5.1 mi |
| 21409 | Annapolis, MD | 5.5 mi |
| 21108 | Millersville, MD | 5.6 mi |
| 21140 | Riva, MD | 5.8 mi |
| 21054 | Gambrills, MD | 6.5 mi |
| 21122 | Pasadena, MD | 6.5 mi |
| 21403 | Annapolis, MD | 6.6 mi |
| 21056 | Gibson Island, MD | 7 mi |
Questions about 21405
What is the ZIP+4 code for 21405?
21405 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 21405, you need to look up a specific street address to get them.
What city is 21405?
21405 is assigned to Annapolis, Maryland, in Anne Arundel 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.