ZIP Code 13603 — Watertown, NY
13603 is a standard (street delivery) ZIP code serving Watertown, New York, in Jefferson 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 13603 at a glance
| ZIP code | 13603 |
|---|---|
| Primary city | Watertown |
| State | New York (NY) |
| County | Jefferson FIPS 36045 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 14,136 |
| Coordinates | 44.038260, -75.797650 |
How ZIP+4 works in 13603
The four digits after the hyphen encode a delivery segment inside 13603. 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 13603 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 Watertown
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 13603.
| ZIP | City | Distance |
|---|---|---|
| 13602 | Fort Drum, NY | 2.1 mi |
| 13638 | Felts Mills, NY | 2.5 mi |
| 13616 | Calcium, NY | 3.2 mi |
| 13612 | Black River, NY | 3.9 mi |
| 13643 | Great Bend, NY | 4 mi |
| 13637 | Evans Mills, NY | 4.5 mi |
| 13628 | Deferiet, NY | 5.7 mi |
| 13601 | Watertown, NY | 7.3 mi |
| 13615 | Brownville, NY | 9.5 mi |
| 13673 | Philadelphia, NY | 9.9 mi |
| 13619 | Carthage, NY | 10.9 mi |
| 13656 | La Fargeville, NY | 13 mi |
Questions about 13603
What is the ZIP+4 code for 13603?
13603 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 13603, you need to look up a specific street address to get them.
What city is 13603?
13603 is assigned to Watertown, New York, in Jefferson 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.