Residential delivery area · Kentucky
ZIP Code 40121: Fort Knox, KY
ZIP code 40121 uses the postal name Fort Knox, Kentucky and lies mostly in Hardin County (84% of its land) with the rest in Meade County (Census 2020 ZIP-county file). About 8,800 people live there (Census Bureau, ACS 2020-2024). Median household income is $82,663 (Census Bureau, ACS 2020-2024). By Census place, 43% of its land lies in Fort Knox (a census-designated place); 57% is outside any Census place.
- ACS2020-24
- Census2020
- ZBP2023
- IRS2022
- Town
- Fort Knox · its only residential ZIP
- County
- Hardin County (84%); Meade County (16%)
- Census places
- Fort Knox census-designated place
- Metro area
- Elizabethtown, KY
- House district
- KY-2 119th Congress
- State
- Kentucky
- Time zone
- Eastern
- Land area
- 35.2 sq mi · 251 people per sq mi
- PO Box ZIPs
- 40122 also use the name Fort Knox
Where is ZIP code 40121?
40121 centers on 37.927°, -85.960° and covers 35.2 square miles of land plus 0.1 of water. It borders 4 ZIP codes: 40155, 40177, 40160, 40165.
The map draws ZIP code areas only. For the streets inside 40121, open its center on OpenStreetMap.
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries and the 2023 Gazetteer (2020 ZCTAs); ZIP-to-county shares, Census places and House districts (119th Congress) from the Census 2020 relationship files (shares of land); metro area from the OMB delineation (July 2023); town name and time zone from simplemaps US ZIP Codes (CC BY 4.0).
How does 40121 compare with the rest of Hardin County?
| Measure | 40121 | In Hardin County | In KY |
|---|---|---|---|
| People (ACS 2020-2024) | 8,836 | 4th of 16 | 144th of 780 |
| Median household income | $83k | 2nd of 10 | 47th of 310 |
| Median home value | – | – | – |
Its median household income is higher than in 65% of U.S. residential ZIP codes, and it is denser than 65% of all U.S. residential ZIP codes. ZIP codes at the ACS caps ($250,000 or more for household income, $2,000,000 or more for home value) share the top rank.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B19013, B25077); ranks by PlainZIP over residential ZIP codes (ZCTAs).
How many people live in 40121?
The 2020 Census counted 7,749 people in 40121; the ACS, which samples households over 2020-2024, estimates 8,836. Its boundary changed between the 2010 and 2020 censuses, so the two counts are not compared.
- People, ACS 2020-2024
- 8,836
- 2020 Census count
- 7,749
- Households
- 2,226
- Median age
- 24.0
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B01002, B11001); 2020 Census (DHC P1); 2010 Census (SF1 P1).
Who lives in 40121?
Of the 8,836 people the ACS estimates in 40121, 33.5% are under 18 and 1.8% are 65 or older. The largest group by race and Hispanic origin is White (not Hispanic) (50.1%), then Hispanic or Latino (22.7%).
- Under 1833.5%
- 18 to 6464.7%
- 65 and older1.8%
- White, not Hispanic50.1%
- Hispanic or Latino22.7%
- Black, not Hispanic15.3%
- Other or two or more9.4%
- Asian, not Hispanic2.6%
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01001 age by sex, B03002 Hispanic or Latino origin by race); shares of the estimated population, small ZIP codes carry wide margins.
What do households in 40121 earn?
Median household income is $82,663 (ACS 2020-2024), the 2nd highest of the 10 ranked ZIP codes in Hardin County.
- Median household income
- $82,663±$14,292
- Income per person
- $32,370
- Below the poverty line
- 9.0%
- Unemployed (of the labor force)
- 15.1%
- Adults 25+ with a bachelor's degree
- 48.3%
- Adjusted gross income per tax return, 2022
- $67,5652,480 returns; wages 93% of AGI (IRS)
Source: U.S. Census Bureau, ACS 2020-2024 and 2015-2019 5-year estimates (B19013, B19301, B17001, B23025, B15003; 2015-2019 dollars converted with the BLS CPI-U, 1.22699); IRS Statistics of Income, ZIP code data, tax year 2022 (adjusted gross income per return, filed under the address on the return).
What are homes worth in 40121?
- Median home value (owners' estimate)
- –
- Median gross rent
- $1,502
- Homes owned by their occupants
- 0.0%
- Housing units
- 2,497
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B25077, B25064, B25003, B25001).
What businesses are in 40121?
55 business establishments had a location in this ZIP code in 2023, 11 fewer than in 2018; the most are in professional, scientific, and technical services (ZIP Code Business Patterns).
- Professional, scientific, and technical services14
- Administrative and support and waste management and remediation services9
- Accommodation and food services6
- Other services (except public administration)6
- Retail trade5
- Finance and insurance4
Source: U.S. Census Bureau, ZIP Code Business Patterns 2023 and 2018 (establishments with paid employees, by the business's ZIP code).
Which ZIP codes are next to 40121?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 40155 | Muldraugh | 1,127 | $61k | 2.4 mi |
| 40177 | West Point | 1,523 | $51k | 5.6 mi |
| 40160 | Radcliff | 23,624 | $59k | 8.0 mi |
| 40165 | Shepherdsville | 38,403 | $80k | 15.1 mi |
| 40117 | Ekron | 2,050 | $59k | 9.2 mi (near) |
| 40175 | Vine Grove | 15,718 | $78k | 10.3 mi (near) |
| 47135 | Laconia, IN | 1,257 | $49k | 10.5 mi (near) |
| 40108 | Brandenburg | 12,821 | $78k | 12.0 mi (near) |
| 40272 | Louisville | 38,289 | $70k | 12.0 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.
Which other ZIP codes use the name Fort Knox?
1 more ZIP code carries the postal name Fort Knox, KY without a residential delivery area: PO boxes at the post office, or a single organization with its own ZIP code. The Census Bureau publishes no figures for it.
| ZIP | County |
|---|---|
| 40122 | Hardin County |
Source: GeoNames postal codes (CC BY 4.0), downloaded 2026-10-09; a ZIP code with no Census ZCTA has no residential delivery area.