ZIP Codes of Knox County, IN

Population & People
Population & People
Total Population
36,177
Household Income
Household Income
Median Income
$66,168
Housing
Housing
Total Housing Units
17,088
Business & Economy
Business & Economy
Total Businesses
874
Employment
Employment
Employment Rate
59.14%
Education
Education
Bachelor's Degree+
18.94%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 12 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:12 ZIP Codes (10 Standard, 2 PO Box, 0 Unique) [See All]
Area Codes:812 / 930
Timezone:Eastern (GMT -05:00)
Local Time:2:12:07 PM
Population:36,177 [See All]
FIPS:18083
CBSA:Vincennes, IN
Land Area:539 sq mi
Water Area:8 sq mi
Coordinates:38.7455, -87.3608
Quick Link:
https://www.zip-codes.com/county/in-knox.asp
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Extreme geographic sprawl
The largest ZIP spans 363× the smallest by area — 164.8 sq mi down to 0.45.

Standout ZIPs in this County


Most Populous
Vincennes · 25,168 people
69.6% of county total
Highest Income
Monroe City · $84,375 median
1.3× county average
Largest Land Area
Vincennes · 164.8 sq mi
Spans the most ground
Fastest Growth
Oaktown · 32.7% (10-yr)
1,087 → 1,442 residents
Most Educated
Vincennes · 21.6% bachelor's+
3,593 of 16,650 adults 25+

Things worth knowing about Knox County


36,177 residents live across 12 ZIPs covering 539 sq mi, served by 12 distinct USPS-recognized cities.

Population moved from 38,325 to 36,157 from 2014 to 2024 — a -5.7% change. 4 ZIPs gained residents, 7 lost.

The county's wealthiest ZIP 47557 (Monroe City, $84,375 median) and poorest ZIP 47561 (Oaktown, $45,911) are 19.1 miles apart — a 1.8× income gap across local geography.

Median home values vary 2.5× across this county — from $71,800 in 47512 (Bicknell) to $182,300 in 47516 (Bruceville).

Density varies 105× across the county — from 6 people/sq mi in 47524 (Decker) to 609 in 47535 (Freelandville).

Educational attainment ranges from 3.2% bachelor's+ in 47597 (Wheatland) to 23.4% in 47557 (Monroe City) — the breadth of educational profiles across the area.

Within Indiana, this is the #45 most populous of 92 counties and ranks #66 for median household income .

Weighted by population, the typical household earns about $61,981 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 (4,615 of 24,370 reporting).

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

Stories about Knox County


Big & sparse

A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.

Total area
539
square miles
Avg density
67.1
people per sq mi
Population
36,177
across 12 ZIPs
Vincennes
164.8 sq mi
25,168 residents
Oaktown
71.1 sq mi
1,442 residents
Decker
52.3 sq mi
302 residents

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.

Vincennes

Population decline

Knox County lost 5.6% of residents between 2014 and 2024. ZIPs that shed the largest share:

Decker
-51.3%
620 → 302 residents
Wheatland
-38.9%
1,220 → 745 residents
Bruceville
-31.4%
1,440 → 988 residents
Sandborn
-19.7%
705 → 566 residents
Edwardsport
-16.1%
545 → 457 residents

All ZIP Codes in Knox County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
47591VincennesStandard25,168$61,803164.8-6.8%
47512BicknellStandard4,243$57,85745.612.4%
47561OaktownStandard1,442$45,91171.132.7%
47557Monroe CityStandard1,345$84,37546.5-2.4%
47516BrucevilleStandard988$76,25033.5-31.4%
47535FreelandvillePO Box807$70,2361.370.6%
47597WheatlandStandard745$56,95342.5-38.9%
47578SandbornStandard566$56,64149.7-19.7%
47528EdwardsportStandard457$57,69229.2-16.1%
47524DeckerStandard30252.3-51.3%
47596WestphaliaPO Box94$93,9582.011.9%
47573RagsdaleStandard200.5

Adjacent & Nearby Counties