ZIP Code 11791 — Syosset, NY
11791 is a standard (street delivery) ZIP code serving Syosset, New York, in Nassau 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 11791 at a glance
| ZIP code | 11791 |
|---|---|
| Primary city | Syosset |
| State | New York (NY) |
| County | Nassau FIPS 36059 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 25,520 |
| Coordinates | 40.828190, -73.502820 |
How ZIP+4 works in 11791
The four digits after the hyphen encode a delivery segment inside 11791. 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 11791 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 11791.
| ZIP | City | Distance |
|---|---|---|
| 11797 | Woodbury, NY | 1.9 mi |
| 11732 | East Norwich, NY | 2.1 mi |
| 11771 | Oyster Bay, NY | 3 mi |
| 11753 | Jericho, NY | 3.3 mi |
| 11803 | Plainview, NY | 3.6 mi |
| 11724 | Cold Spring Harbor, NY | 3.7 mi |
| 11545 | Glen Head, NY | 4.5 mi |
| 11801 | Hicksville, NY | 4.7 mi |
| 11765 | Mill Neck, NY | 4.7 mi |
| 11804 | Old Bethpage, NY | 5.4 mi |
| 11743 | Huntington, NY | 5.4 mi |
| 11548 | Greenvale, NY | 5.7 mi |
Questions about 11791
What is the ZIP+4 code for 11791?
11791 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 11791, you need to look up a specific street address to get them.
What city is 11791?
11791 is assigned to Syosset, New York, in Nassau 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.