ZIP Code 42123 — Austin, KY
42123 is a standard (street delivery) ZIP code serving Austin, Kentucky, in Barren 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 42123 at a glance
| ZIP code | 42123 |
|---|---|
| Primary city | Austin |
| State | Kentucky (KY) |
| County | Barren FIPS 21009 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 1,149 |
| Coordinates | 36.820390, -85.995730 |
How ZIP+4 works in 42123
The four digits after the hyphen encode a delivery segment inside 42123. 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 42123 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 42123.
| ZIP | City | Distance |
|---|---|---|
| 42156 | Lucas, KY | 4 mi |
| 42131 | Etoile, KY | 4.8 mi |
| 42133 | Fountain Run, KY | 7.1 mi |
| 42141 | Glasgow, KY | 9.9 mi |
| 42157 | Mount Hermon, KY | 10 mi |
| 42153 | Holland, KY | 10 mi |
| 42164 | Scottsville, KY | 10.8 mi |
| 42130 | Eighty Eight, KY | 13.9 mi |
| 42140 | Gamaliel, KY | 14.6 mi |
| 42166 | Summer Shade, KY | 16 mi |
| 42171 | Smiths Grove, KY | 17.6 mi |
| 42120 | Adolphus, KY | 18.5 mi |
Questions about 42123
What is the ZIP+4 code for 42123?
42123 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 42123, you need to look up a specific street address to get them.
What city is 42123?
42123 is assigned to Austin, Kentucky, in Barren 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.