ZIP Codes of Simpson County, KY

Population & People
Population & People
Total Population
19,380
Household Income
Household Income
Median Income
$59,113
Housing
Housing
Total Housing Units
8,326
Business & Economy
Business & Economy
Total Businesses
405
Employment
Employment
Employment Rate
57.13%
Education
Education
Bachelor's Degree+
18.87%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 2 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:2 ZIP Codes (1 Standard, 1 PO Box, 0 Unique) [See All]
Area Codes:270 / 364
Timezone:Central (GMT -06:00)
Local Time:2:12:22 PM
Population:19,380 [See All]
FIPS:21213
CBSA:Franklin, KY
Land Area:213 sq mi
Water Area:2 sq mi
Coordinates:36.7332, -86.5741
Quick Link:
https://www.zip-codes.com/county/ky-simpson.asp
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Among Kentucky's 5 fastest-growing counties
#5 statewide, up 15.9% from 2014 to 2024.

Standout ZIPs in this County


Most Populous
Franklin · 19,380 people
100.0% of county total
Highest Income
Franklin · $59,113 median
1.0× county average
Largest Land Area
Franklin · 213.5 sq mi
Spans the most ground
Fastest Growth
Franklin · 15.9% (10-yr)
16,723 → 19,380 residents
Most Educated
Franklin · 18.9% bachelor's+
2,483 of 13,156 adults 25+

Things worth knowing about Simpson County


19,380 residents live across 2 ZIPs covering 213 sq mi, served by 1 distinct USPS-recognized cities.

Population moved from 16,723 to 19,380 from 2014 to 2024 — a +15.9% change. 1 ZIPs gained residents, 0 lost.

The county's wealthiest ZIP 42134 (Franklin, $59,113 median) and poorest ZIP 42134 (Franklin, $59,113) are 0.0 miles apart — a 1.0× income gap across local geography.

Within Kentucky, this is the #57 most populous of 120 counties and ranks #57 for median household income with the #5 fastest decade growth .

Weighted by population, the typical household earns about $59,113 across the county — reflecting what a typical resident sees, not a simple ZIP average.

18.9% of adults age 25+ hold a bachelor's degree or higher (2,483 of 13,156 reporting).

1 Standard delivery, 1 PO Box only, 0 single-entity Unique ZIPs serve this county.

All ZIP Codes in Simpson County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
42134FranklinStandard19,380$59,113213.515.9%
42135FranklinPO Box0.0

Adjacent & Nearby Counties