ZIP Code 45231 — Cincinnati, OH
45231 is a standard (street delivery) ZIP code serving Cincinnati, Ohio, in Hamilton 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 45231 at a glance
| ZIP code | 45231 |
|---|---|
| Primary city | Cincinnati |
| State | Ohio (OH) |
| County | Hamilton FIPS 39061 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 40,463 |
| Coordinates | 39.246170, -84.538300 |
How ZIP+4 works in 45231
The four digits after the hyphen encode a delivery segment inside 45231. 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 45231 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.
Other ZIP codes in Cincinnati
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 45231.
| ZIP | City | Distance |
|---|---|---|
| 45218 | Cincinnati, OH | 1.7 mi |
| 45240 | Cincinnati, OH | 2.7 mi |
| 45224 | Cincinnati, OH | 3.1 mi |
| 45251 | Cincinnati, OH | 3.3 mi |
| 45239 | Cincinnati, OH | 3.6 mi |
| 45215 | Cincinnati, OH | 4.1 mi |
| 45216 | Cincinnati, OH | 4.4 mi |
| 45232 | Cincinnati, OH | 4.6 mi |
| 45246 | Cincinnati, OH | 4.9 mi |
| 45223 | Cincinnati, OH | 5.3 mi |
| 45252 | Cincinnati, OH | 5.4 mi |
| 45014 | Fairfield, OH | 5.7 mi |
Questions about 45231
What is the ZIP+4 code for 45231?
45231 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 45231, you need to look up a specific street address to get them.
What city is 45231?
45231 is assigned to Cincinnati, Ohio, in Hamilton 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.