ZIP Code 03603 — Charlestown, NH
03603 is a standard (street delivery) ZIP code serving Charlestown, New Hampshire, in Sullivan 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 03603 at a glance
| ZIP code | 03603 |
|---|---|
| Primary city | Charlestown |
| State | New Hampshire (NH) |
| County | Sullivan FIPS 33019 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 5,238 |
| Coordinates | 43.253390, -72.380590 |
How ZIP+4 works in 03603
The four digits after the hyphen encode a delivery segment inside 03603. 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 03603 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 03603.
| ZIP | City | Distance |
|---|---|---|
| 03601 | Acworth, NH | 4.2 mi |
| 05156 | Springfield, VT | 5.8 mi |
| 03607 | South Acworth, NH | 7.2 mi |
| 05101 | Bellows Falls, VT | 7.3 mi |
| 03743 | Claremont, NH | 7.9 mi |
| 03609 | North Walpole, NH | 8.2 mi |
| 03604 | Drewsville, NH | 8.4 mi |
| 03602 | Alstead, NH | 8.4 mi |
| 05150 | North Springfield, VT | 9.3 mi |
| 05030 | Ascutney, VT | 10.2 mi |
| 03605 | Lempster, NH | 10.2 mi |
| 05154 | Saxtons River, VT | 11.2 mi |
Questions about 03603
What is the ZIP+4 code for 03603?
03603 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 03603, you need to look up a specific street address to get them.
What city is 03603?
03603 is assigned to Charlestown, New Hampshire, in Sullivan 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.