ZIP Code 46321 — Munster, IN
46321 is a standard (street delivery) ZIP code serving Munster, Indiana, in Lake 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 46321 at a glance
| ZIP code | 46321 |
|---|---|
| Primary city | Munster |
| State | Indiana (IN) |
| County | Lake FIPS 18089 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 23,733 |
| Coordinates | 41.547040, -87.504020 |
How ZIP+4 works in 46321
The four digits after the hyphen encode a delivery segment inside 46321. 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 46321 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 46321.
| ZIP | City | Distance |
|---|---|---|
| 46322 | Highland, IN | 2.3 mi |
| 46324 | Hammond, IN | 2.5 mi |
| 60438 | Lansing, IL | 2.7 mi |
| 46323 | Hammond, IN | 3.9 mi |
| 46320 | Hammond, IN | 4.3 mi |
| 46319 | Griffith, IN | 4.6 mi |
| 46375 | Schererville, IN | 4.7 mi |
| 60409 | Calumet City, IL | 5.2 mi |
| 60411 | Chicago Heights, IL | 5.2 mi |
| 46311 | Dyer, IN | 5.4 mi |
| 60476 | Thornton, IL | 5.5 mi |
| 60425 | Glenwood, IL | 5.5 mi |
Questions about 46321
What is the ZIP+4 code for 46321?
46321 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 46321, you need to look up a specific street address to get them.
What city is 46321?
46321 is assigned to Munster, Indiana, in Lake 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.