ZIP Code 03837 — Gilmanton Iron Works, NH
03837 is a standard (street delivery) ZIP code serving Gilmanton Iron Works, New Hampshire, in Belknap 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 03837 at a glance
| ZIP code | 03837 |
|---|---|
| Primary city | Gilmanton Iron Works |
| State | New Hampshire (NH) |
| County | Belknap FIPS 33001 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 1,451 |
| Coordinates | 43.422710, -71.327660 |
How ZIP+4 works in 03837
The four digits after the hyphen encode a delivery segment inside 03837. 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 03837 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 03837.
| ZIP | City | Distance |
|---|---|---|
| 03237 | Gilmanton, NH | 2.8 mi |
| 03225 | Center Barnstead, NH | 6.2 mi |
| 03809 | Alton, NH | 6.2 mi |
| 03218 | Barnstead, NH | 6.4 mi |
| 03810 | Alton Bay, NH | 7.6 mi |
| 03220 | Belmont, NH | 8.1 mi |
| 03263 | Pittsfield, NH | 8.9 mi |
| 03307 | Loudon, NH | 9 mi |
| 03855 | New Durham, NH | 9.7 mi |
| 03249 | Gilford, NH | 9.8 mi |
| 03224 | Canterbury, NH | 12 mi |
| 03258 | Chichester, NH | 12 mi |
Questions about 03837
What is the ZIP+4 code for 03837?
03837 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 03837, you need to look up a specific street address to get them.
What city is 03837?
03837 is assigned to Gilmanton Iron Works, New Hampshire, in Belknap 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.