Posey County, Indiana
County seat: Mount Vernon · Population 24,988 (2025) · 409 sq mi
Posey County is the 63rd most populous of Indiana's 92 counties, with 24,988 people (2025 estimate). Its county seat is Mount Vernon. It is part of the Southwest (Region 11) region, one of the 12 Indiana economic growth regions (DWD / WorkOne regions). The map shows its 5 cities and towns and the 6 neighboring counties.
Posey County facts
- County seat
- Mount Vernon
- Population (2025 estimate)
- 24,988 −1% since 2020
- Land area
- 409 sq mi 35th largest of 92
- Water area
- 10 sq mi
- Population density
- 61 per sq mi
- Established
- 1814
- Named after
- Thomas Posey American politician (1750-1818)
- Largest city
- Mount Vernon 6,289
- Median household income
- $78,129
- Cities and towns
- 5 plus 5 CDPs
- ZIP codes
- 7
- Time zone
- Central
- FIPS code
- 18129
Cities and towns in Posey County
Posey County has 5 incorporated cities, towns and villages. Populations count the people living inside Posey County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Mount Vernon (county seat) | City | 6,289 | |
| Poseyville | Town | 966 | |
| New Harmony | Town | 680 | |
| Cynthiana | Town | 552 | |
| Griffin | Town | 139 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Wadesville | 672 | |
| St. Wendel | 671 | Vanderburgh County |
| Parkers Settlement | 605 | |
| Stewartsville | 206 | |
| Blairsville | 203 |
ZIP codes in Posey County
7 ZIP codes reach into Posey County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 47612 also Gibson County
- 47616 also Gibson County
- 47620
- 47631
- 47633 also Gibson and Vanderburgh counties
- 47638
- 47712 also Vanderburgh County
Population of Posey County, 2020–2025
Posey County shrank by 239 people (−1%) between April 2020 and July 2025: 240 more deaths than births and a net gain of 9 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 25,190 |
| 2021 | 25,160 |
| 2022 | 25,081 |
| 2023 | 25,024 |
| 2024 | 25,058 |
| 2025 | 24,988 |
Neighboring counties
- White County, Illinois west · 13,250 people
- Gibson County northeast · 33,091 people
- Vanderburgh County east · 181,995 people
- Union County, Kentucky south · 12,839 people
- Henderson County, Kentucky southeast · 44,255 people
- Gallatin County, Illinois southwest · 4,616 people
Printable Posey 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) (113 KB)
- PNG (2400 px) (123 KB)
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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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