ZIP Code 06340 — Groton, CT
06340 is a standard (street delivery) ZIP code serving Groton, Connecticut, in Southeastern 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 06340 at a glance
| ZIP code | 06340 |
|---|---|
| Primary city | Groton |
| State | Connecticut (CT) |
| County | Southeastern Connecticut FIPS 09180 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 29,863 |
| Coordinates | 41.356430, -72.044770 |
How ZIP+4 works in 06340
The four digits after the hyphen encode a delivery segment inside 06340. 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 06340 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 06340.
| ZIP | City | Distance |
|---|---|---|
| 06320 | New London, CT | 3 mi |
| 06355 | Mystic, CT | 3.7 mi |
| 06335 | Gales Ferry, CT | 5.1 mi |
| 06375 | Quaker Hill, CT | 5.4 mi |
| 06385 | Waterford, CT | 5.8 mi |
| 06339 | Ledyard, CT | 6.5 mi |
| 06390 | Fishers Island, NY | 6.6 mi |
| 06378 | Stonington, CT | 7 mi |
| 06382 | Uncasville, CT | 8.2 mi |
| 06353 | Montville, CT | 8.4 mi |
| 06338 | Mashantucket, CT | 8.4 mi |
| 06357 | Niantic, CT | 9 mi |
Questions about 06340
What is the ZIP+4 code for 06340?
06340 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 06340, you need to look up a specific street address to get them.
What city is 06340?
06340 is assigned to Groton, Connecticut, in Southeastern 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.