ZIP Codes of Dekalb County, IN

Population & People
Population & People
Total Population
42,541
Household Income
Household Income
Median Income
$76,248
Housing
Housing
Total Housing Units
17,857
Business & Economy
Business & Economy
Total Businesses
999
Employment
Employment
Employment Rate
63.74%
Education
Education
Bachelor's Degree+
21.32%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 7 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:7 ZIP Codes (7 Standard, 0 PO Box, 0 Unique) [See All]
Area Code:260
Timezone:Eastern (GMT -05:00)
Local Time:2:12:05 PM
Population:42,541 [See All]
FIPS:18033
CBSA:Auburn, IN
Land Area:324 sq mi
Water Area:1 sq mi
Coordinates:41.4064, -85.0278
Quick Link:
https://www.zip-codes.com/county/in-dekalb.asp
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Indiana's #35 most populous county
42,541 residents across 7 ZIPs — #35 of 92 Indiana counties.

Standout ZIPs in this County


Most Populous
Auburn · 20,403 people
48.0% of county total
Highest Income
Corunna · $116,181 median
1.5× county average
Largest Land Area
Auburn · 90.8 sq mi
Spans the most ground
Fastest Growth
Ashley · 15.5% (10-yr)
1,707 → 1,972 residents
Most Educated
Auburn · 27.0% bachelor's+
3,741 of 13,860 adults 25+

Things worth knowing about Dekalb County


42,541 residents live across 7 ZIPs covering 324 sq mi, served by 7 distinct USPS-recognized cities.

Population moved from 41,174 to 42,541 from 2014 to 2024 — a +3.3% change. 4 ZIPs gained residents, 3 lost.

The county's wealthiest ZIP 46730 (Corunna, $116,181 median) and poorest ZIP 46738 (Garrett, $57,545) are 8.9 miles apart — a 2.0× income gap across local geography.

Median home values vary 2.3× across this county — from $138,800 in 46721 (Butler) to $316,500 in 46730 (Corunna).

Density varies across the county — from 44 people/sq mi in 46730 (Corunna) to 343 in 46738 (Garrett).

Educational attainment ranges from 6.5% bachelor's+ in 46785 (Saint Joe) to 27.0% in 46706 (Auburn) — the breadth of educational profiles across the area.

Within Indiana, this is the #35 most populous of 92 counties and ranks #30 for median household income .

Weighted by population, the typical household earns about $74,609 across the county — reflecting what a typical resident sees, not a simple ZIP average.

21.3% of adults age 25+ hold a bachelor's degree or higher (6,174 of 28,952 reporting).

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

All ZIP Codes in Dekalb County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
46706AuburnStandard20,403$80,96590.86.8%
46738GarrettStandard8,533$57,54524.98.6%
46721ButlerStandard4,739$68,58078.3-7.2%
46793WaterlooStandard4,104$79,94955.4-4.8%
46705AshleyStandard1,972$67,26620.315.5%
46785Saint JoeStandard1,491$63,25024.6-21.9%
46730CorunnaStandard1,299$116,18129.39.6%

Adjacent & Nearby Counties