ZIP Codes of Mercer County, KY

Population & People
Population & People
Total Population
23,811
Household Income
Household Income
Median Income
$64,891
Housing
Housing
Total Housing Units
10,806
Business & Economy
Business & Economy
Total Businesses
365
Employment
Employment
Employment Rate
55.98%
Education
Education
Bachelor's Degree+
24.99%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 3 ZIPs in this county.
Data Last Updated: July 1, 2026
ZIP Codes:3 ZIP Codes (2 Standard, 1 PO Box, 0 Unique) [See All]
Area Code:859
Timezone:Eastern (GMT -05:00)
Local Time:11:53:39 PM
Population:23,811 [See All]
FIPS:21167
Land Area:279 sq mi
Water Area:4 sq mi
Coordinates:37.8216, -84.8461
Quick Link:
https://www.zip-codes.com/county/ky-mercer.asp
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Kentucky's #48 most populous county
23,811 residents across 3 ZIPs — #48 of 120 Kentucky counties.

Standout ZIPs in this County


Most Populous
Harrodsburg · 21,250 people
89.2% of county total
Highest Income
Salvisa · $74,205 median
1.1× county average
Largest Land Area
Harrodsburg · 222.6 sq mi
Spans the most ground
Fastest Growth
Harrodsburg · 13.4% (10-yr)
18,747 → 21,250 residents
Most Educated
Harrodsburg · 25.3% bachelor's+
3,742 of 14,790 adults 25+

Things worth knowing about Mercer County


23,811 residents live across 3 ZIPs covering 279 sq mi, served by 3 distinct USPS-recognized cities.

Population moved from 21,760 to 23,811 from 2014 to 2024 — a +9.4% change. 1 ZIPs gained residents, 2 lost.

The county's wealthiest ZIP 40372 (Salvisa, $74,205 median) and poorest ZIP 40310 (Burgin, $56,477) are 13.7 miles apart — a 1.3× income gap across local geography.

Median home values vary 1.8× across this county — from $126,600 in 40310 (Burgin) to $229,800 in 40372 (Salvisa).

Density varies 239× across the county — from 37 people/sq mi in 40372 (Salvisa) to 8,904 in 40310 (Burgin).

Educational attainment ranges from 19.3% bachelor's+ in 40310 (Burgin) to 25.3% in 40330 (Harrodsburg) — the breadth of educational profiles across the area.

Within Kentucky, this is the #48 most populous of 120 counties and ranks #35 for median household income with the #17 fastest decade growth .

Weighted by population, the typical household earns about $64,740 across the county — reflecting what a typical resident sees, not a simple ZIP average.

25.0% of adults age 25+ hold a bachelor's degree or higher (4,150 of 16,609 reporting).

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

Stories about Mercer County


Single-ZIP anchor

One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.

Harrodsburg

All ZIP Codes in Mercer County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
40330HarrodsburgStandard21,250$63,992222.613.4%
40372SalvisaStandard2,090$74,20556.1-12.4%
40310BurginPO Box471$56,4770.1-24.8%

Adjacent & Nearby Counties