ZIP Code 06423 — East Haddam, CT
06423 is a standard (street delivery) ZIP code serving East Haddam, Connecticut, in Lower Connecticut River Valley 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 06423 at a glance
| ZIP code | 06423 |
|---|---|
| Primary city | East Haddam |
| State | Connecticut (CT) |
| County | Lower Connecticut River Valley FIPS 09130 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 5,182 |
| Coordinates | 41.466540, -72.390540 |
How ZIP+4 works in 06423
The four digits after the hyphen encode a delivery segment inside 06423. 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 06423 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 06423.
| ZIP | City | Distance |
|---|---|---|
| 06439 | Hadlyme, CT | 3.5 mi |
| 06469 | Moodus, CT | 4.2 mi |
| 06438 | Haddam, CT | 6.1 mi |
| 06412 | Chester, CT | 6.4 mi |
| 06420 | Salem, CT | 6.5 mi |
| 06415 | Colchester, CT | 6.5 mi |
| 06417 | Deep River, CT | 7.7 mi |
| 06426 | Essex, CT | 7.8 mi |
| 06371 | Old Lyme, CT | 7.9 mi |
| 06409 | Centerbrook, CT | 8.1 mi |
| 06424 | East Hampton, CT | 8.7 mi |
| 06442 | Ivoryton, CT | 9 mi |
Questions about 06423
What is the ZIP+4 code for 06423?
06423 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 06423, you need to look up a specific street address to get them.
What city is 06423?
06423 is assigned to East Haddam, Connecticut, in Lower Connecticut River Valley 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.