ZIP Code 42171 — Smiths Grove, KY
42171 is a standard (street delivery) ZIP code serving Smiths Grove, Kentucky, in Warren 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 42171 at a glance
| ZIP code | 42171 |
|---|---|
| Primary city | Smiths Grove |
| State | Kentucky (KY) |
| County | Warren FIPS 21227 |
| ZIP type | Standard (street delivery) |
| Time zone | America/Chicago |
| Population | 6,723 |
| Coordinates | 37.036090, -86.167280 |
How ZIP+4 works in 42171
The four digits after the hyphen encode a delivery segment inside 42171. 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 42171 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 42171.
| ZIP | City | Distance |
|---|---|---|
| 42163 | Rocky Hill, KY | 3.5 mi |
| 42159 | Oakland, KY | 5.2 mi |
| 42160 | Park City, KY | 6.7 mi |
| 42103 | Bowling Green, KY | 11 mi |
| 42259 | Mammoth Cave, KY | 13.7 mi |
| 42156 | Lucas, KY | 13.8 mi |
| 42127 | Cave City, KY | 14.5 mi |
| 42210 | Brownsville, KY | 14.9 mi |
| 42141 | Glasgow, KY | 15.1 mi |
| 42122 | Alvaton, KY | 16.1 mi |
| 42101 | Bowling Green, KY | 17.2 mi |
| 42285 | Sweeden, KY | 17.3 mi |
Questions about 42171
What is the ZIP+4 code for 42171?
42171 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 42171, you need to look up a specific street address to get them.
What city is 42171?
42171 is assigned to Smiths Grove, Kentucky, in Warren 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.