ZIP Code 42603 — Alpha, KY
42603 is a standard (street delivery) ZIP code serving Alpha, Kentucky, in Wayne 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 42603 at a glance
| ZIP code | 42603 |
|---|---|
| Primary city | Alpha |
| State | Kentucky (KY) |
| County | Wayne FIPS 21231 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Kentucky/Monticello |
| Population | 694 |
| Coordinates | 36.778750, -85.010930 |
How ZIP+4 works in 42603
The four digits after the hyphen encode a delivery segment inside 42603. 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 42603 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 42603.
| ZIP | City | Distance |
|---|---|---|
| 42602 | Albany, KY | 7.5 mi |
| 42633 | Monticello, KY | 10 mi |
| 42629 | Jamestown, KY | 11.7 mi |
| 38577 | Pall Mall, TN | 15.2 mi |
| 38549 | Byrdstown, TN | 16.9 mi |
| 42642 | Russell Springs, KY | 19.2 mi |
| 42741 | Glens Fork, KY | 19.7 mi |
| 42717 | Burkesville, KY | 20.6 mi |
| 42544 | Nancy, KY | 20.7 mi |
| 42518 | Bronston, KY | 22.7 mi |
| 42647 | Stearns, KY | 22.9 mi |
| 38573 | Monroe, TN | 23 mi |
Questions about 42603
What is the ZIP+4 code for 42603?
42603 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 42603, you need to look up a specific street address to get them.
What city is 42603?
42603 is assigned to Alpha, Kentucky, in Wayne 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.