ZIP Code 06437 — Guilford, CT
06437 is a standard (street delivery) ZIP code serving Guilford, Connecticut, in South Central Connecticut 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 06437 at a glance
| ZIP code | 06437 |
|---|---|
| Primary city | Guilford |
| State | Connecticut (CT) |
| County | South Central Connecticut FIPS 09170 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 22,067 |
| Coordinates | 41.334440, -72.700510 |
How ZIP+4 works in 06437
The four digits after the hyphen encode a delivery segment inside 06437. 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 06437 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 06437.
| ZIP | City | Distance |
|---|---|---|
| 06471 | North Branford, CT | 3.8 mi |
| 06443 | Madison, CT | 3.8 mi |
| 06472 | Northford, CT | 5.3 mi |
| 06405 | Branford, CT | 6.1 mi |
| 06419 | Killingworth, CT | 7 mi |
| 06473 | North Haven, CT | 8.7 mi |
| 06513 | New Haven, CT | 8.8 mi |
| 06422 | Durham, CT | 8.9 mi |
| 06413 | Clinton, CT | 9.2 mi |
| 06512 | East Haven, CT | 9.6 mi |
| 06492 | Wallingford, CT | 10.2 mi |
| 06517 | Hamden, CT | 10.6 mi |
Questions about 06437
What is the ZIP+4 code for 06437?
06437 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 06437, you need to look up a specific street address to get them.
What city is 06437?
06437 is assigned to Guilford, Connecticut, in South Central Connecticut 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.