ZIP Code 06401 — Ansonia, CT
06401 is a standard (street delivery) ZIP code serving Ansonia, Connecticut, in Naugatuck 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 06401 at a glance
| ZIP code | 06401 |
|---|---|
| Primary city | Ansonia |
| State | Connecticut (CT) |
| County | Naugatuck Valley FIPS 09140 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 19,315 |
| Coordinates | 41.344240, -73.068960 |
How ZIP+4 works in 06401
The four digits after the hyphen encode a delivery segment inside 06401. 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 06401 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 06401.
| ZIP | City | Distance |
|---|---|---|
| 06418 | Derby, CT | 1.4 mi |
| 06483 | Seymour, CT | 2.7 mi |
| 06525 | Woodbridge, CT | 3.2 mi |
| 06484 | Shelton, CT | 4.5 mi |
| 06477 | Orange, CT | 4.8 mi |
| 06515 | New Haven, CT | 5.3 mi |
| 06403 | Beacon Falls, CT | 6.6 mi |
| 06514 | Hamden, CT | 6.9 mi |
| 06478 | Oxford, CT | 6.9 mi |
| 06524 | Bethany, CT | 6.9 mi |
| 06461 | Milford, CT | 7.2 mi |
| 06516 | West Haven, CT | 7.2 mi |
Questions about 06401
What is the ZIP+4 code for 06401?
06401 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 06401, you need to look up a specific street address to get them.
What city is 06401?
06401 is assigned to Ansonia, Connecticut, in Naugatuck 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.