ZIP Codes of Mercer County, MO

Population & People
Population & People
Total Population
3,254
Household Income
Household Income
Median Income
$57,743
Housing
Housing
Total Housing Units
1,716
Business & Economy
Business & Economy
Total Businesses
75
Employment
Employment
Employment Rate
55.20%
Education
Education
Bachelor's Degree+
17.24%
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 (2 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:660
Timezone:Central (GMT -06:00)
Local Time:2:12:44 PM
Population:3,254 [See All]
FIPS:29129
Land Area:329 sq mi
Water Area:1 sq mi
Coordinates:40.4550, -93.5420
Quick Link:
https://www.zip-codes.com/county/mo-mercer.asp
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Missouri's #114 most populous county
3,254 residents across 2 ZIPs — #114 of 116 Missouri counties.

Standout ZIPs in this County


Most Populous
Princeton · 2,497 people
76.7% of county total
Highest Income
Princeton · $61,364 median
1.1× county average
Largest Land Area
Princeton · 238.5 sq mi
Spans the most ground
Fastest Growth
Princeton · 9.3% (10-yr)
2,284 → 2,497 residents
Most Educated
Princeton · 18.1% bachelor's+
299 of 1,656 adults 25+

Things worth knowing about Mercer County


3,254 residents live across 2 ZIPs covering 329 sq mi, served by 2 distinct USPS-recognized cities.

Population moved from 3,463 to 3,254 from 2014 to 2024 — a -6.0% change. 1 ZIPs gained residents, 1 lost.

The county's wealthiest ZIP 64673 (Princeton, $61,364 median) and poorest ZIP 64661 (Mercer, $54,122) are 10.1 miles apart — a 1.1× income gap across local geography.

Median home values vary 1.4× across this county — from $73,800 in 64661 (Mercer) to $101,600 in 64673 (Princeton).

Density varies across the county — from 8 people/sq mi in 64661 (Mercer) to 10 in 64673 (Princeton).

Educational attainment ranges from 14.7% bachelor's+ in 64661 (Mercer) to 18.1% in 64673 (Princeton) — the breadth of educational profiles across the area.

Within Missouri, this is the #114 most populous of 116 counties and ranks #75 for median household income .

Weighted by population, the typical household earns about $59,679 across the county — reflecting what a typical resident sees, not a simple ZIP average.

17.2% of adults age 25+ hold a bachelor's degree or higher (377 of 2,187 reporting).

2 Standard delivery, 0 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.

Princeton

Population decline

Mercer County lost 6.0% of residents between 2014 and 2024. ZIPs that shed the largest share:

Mercer
-35.8%
1,179 → 757 residents

All ZIP Codes in Mercer County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
64673PrincetonStandard2,497$61,364238.59.3%
64661MercerStandard757$54,12290.6-35.8%

Adjacent & Nearby Counties