County ZIP codes · Kentucky · FIPS 21185
Oldham County, KY ZIP Codes
Oldham County, Kentucky has 11 ZIP codes (Census 2020 ZCTA-county file; GeoNames postal codes, October 2026): 10 residential and 1 for PO boxes or a single organization. 7 of the residential ones lie mainly in Oldham County and 3 mainly in a neighboring county; 5 cross the county line. Median household income ranges from $80,750 in 40068 (Smithfield) to $152,727 in 40059 (Prospect) (Census Bureau, ACS 2020-2024).
- ACS2020-24
- Census2020
Where are the ZIP codes of Oldham County?
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries; ACS 2020-2024 5-year estimates (B19013).
How different are its ZIP codes?
The middle half of its ranked ZIP codes (1,000+ people living in households) report median household incomes between $94,078 and $134,115.
They carry 10 postal town names.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B19013).
All 10 residential ZIP codes in Oldham County
7 ZIP codes lie mainly in Oldham County; 3 more reach into it from a neighboring county and follow the first table.
| In this county | ||||||
|---|---|---|---|---|---|---|
| 40031 | La Grange | 26,259 | 393 | $99k | $341k | 93% |
| 40014 | Crestwood | 23,101 | 443 | $121k | $394k | 100% |
| 40059 | Prospect | 20,892 | 741 | $153k | $559k | 61% |
| 40026 | Goshen | 5,975 | 193 | $134k | $432k | 100% |
| 40056 | Pewee Valley | 3,441 | 1,165 | $134k | $340k | 100% |
| 40010 | Buckner | 678 | 442 | $196k | $592k | 100% |
| 40077 | Westport | 678 | 87 | $73k | $196k | 100% |
Partly in Oldham County
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates; county shares by land area (Census 2020 ZCTA-county relationship file).
Which ZIP codes cross the county line?
5 ZIP codes of Oldham County extend into another county. A ZIP code follows mail routes, not county borders.
| ZIP | In Oldham | Elsewhere |
|---|---|---|
| 40241 | 2% | Jefferson County 98% |
| 40031 | 93% | Henry County 7% |
| 40059 | 61% | Jefferson County 39% |
| 40068 | 14% | Henry County 69%; Shelby County 17% |
| 40055 | 23% | Trimble County 48%; Henry County 30% |
Source: U.S. Census Bureau, 2020 ZCTA-county relationship file (shares of land area).
PO Box and single-organization ZIP codes
| ZIP | Postal name |
|---|---|
| 40032 | La Grange |
Source: GeoNames postal codes (CC BY 4.0).
Which first three digits do Oldham County's ZIP codes use?
The first three digits of a ZIP code name the sectional center, the mail processing plant that sorts it. Oldham County's ZIP codes use 2 prefixes: 400 and 402.
Source: U.S. Postal Service, labeling list L005 (3-digit ZIP Code prefix groups, SCF sortation), effective October 1, 2026.