DeKalb County, Indiana
County seat: Auburn · Population 44,535 (2025) · 363 sq mi
DeKalb County is the 35th most populous of Indiana's 92 counties, with 44,535 people (2025 estimate). Its county seat is Auburn. It is part of the Northeast (Region 3) region, one of the 12 Indiana economic growth regions (DWD / WorkOne regions). The map shows its 9 cities and towns and the 6 neighboring counties.
DeKalb County facts
- County seat
- Auburn
- Population (2025 estimate)
- 44,535 +2.9% since 2020
- Land area
- 363 sq mi 68th largest of 92
- Water area
- 1 sq mi
- Population density
- 123 per sq mi
- Established
- 1835
- Named after
- Johann de Kalb American general (1721-1780)
- Largest city
- Auburn 14,068
- Median household income
- $74,331
- Cities and towns
- 9 plus 1 CDPs
- ZIP codes
- 14
- Time zone
- Eastern
- FIPS code
- 18033
Cities and towns in DeKalb County
DeKalb County has 9 incorporated cities, towns and villages. Populations count the people living inside DeKalb County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Auburn (county seat) | City | 14,068 | |
| Garrett | City | 6,694 | |
| Butler | City | 2,673 | |
| Waterloo | Town | 2,168 | |
| Ashley | Town | 680 | Steuben County |
| St. Joe | Town | 429 | |
| Hamilton | Town | 244 | Steuben County |
| Corunna | Town | 241 | |
| Altona | Town | 220 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Spencerville | 244 |
ZIP codes in DeKalb County
14 ZIP codes reach into DeKalb County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 46705 also Steuben County
- 46706 also Allen County
- 46710 also Noble County
- 46721
- 46730
- 46738
- 46742 also Steuben County
- 46747 also Steuben and LaGrange counties
- 46748 also Allen and Noble counties
- 46755 also Noble County
- 46763 also Noble County
- 46785
- 46788 also Allen County
- 46793 also Steuben County
Population of DeKalb County, 2020–2025
DeKalb County grew by 1,273 people (+2.9%) between April 2020 and July 2025: 315 more births than deaths and a net gain of 923 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 43,292 |
| 2021 | 43,372 |
| 2022 | 43,737 |
| 2023 | 44,148 |
| 2024 | 44,338 |
| 2025 | 44,535 |
Neighboring counties
- Allen County south · 402,329 people
- Steuben County north · 34,799 people
- Noble County west · 47,937 people
- Defiance County, Ohio east · 38,292 people
- Williams County, Ohio northeast · 36,549 people
- LaGrange County northwest · 41,305 people
Printable DeKalb County map
The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.
- PDF (Letter) (88 KB)
- PNG (2400 px) (68 KB)
Paste this code to embed the map on your site:
Sources
- Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files (1:500,000).
- Population: Census Bureau county and city estimates, Vintage 2025. CDP populations: American Community Survey 2020–2024.
- Places and ZIP codes: Census Bureau 2026 Gazetteer and 2020 ZIP Code Tabulation Area relationship files.
- County seat, founding year and name origin: Wikidata (CC0), checked against state sources.
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