ZIP Code 45123 — Greenfield, OH
45123 is a standard (street delivery) ZIP code serving Greenfield, Ohio, in Highland 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 45123 at a glance
| ZIP code | 45123 |
|---|---|
| Primary city | Greenfield |
| State | Ohio (OH) |
| County | Highland FIPS 39071 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 8,740 |
| Coordinates | 39.348700, -83.388660 |
How ZIP+4 works in 45123
The four digits after the hyphen encode a delivery segment inside 45123. 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 45123 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 45123.
| ZIP | City | Distance |
|---|---|---|
| 45681 | South Salem, OH | 8.1 mi |
| 45135 | Leesburg, OH | 8.5 mi |
| 45628 | Frankfort, OH | 10.6 mi |
| 45612 | Bainbridge, OH | 11.1 mi |
| 45132 | Highland, OH | 11.3 mi |
| 45624 | Cynthiana, OH | 12.3 mi |
| 43160 | Washington Court House, OH | 12.7 mi |
| 45617 | Bourneville, OH | 13.3 mi |
| 43115 | Clarksburg, OH | 15.4 mi |
| 45159 | New Vienna, OH | 16.1 mi |
| 43145 | New Holland, OH | 16.3 mi |
| 45133 | Hillsboro, OH | 16.5 mi |
Questions about 45123
What is the ZIP+4 code for 45123?
45123 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 45123, you need to look up a specific street address to get them.
What city is 45123?
45123 is assigned to Greenfield, Ohio, in Highland 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.