Miami County, Ohio
County seat: Troy · Population 112,634 (2025) · 407 sq mi
Miami County is the 25th most populous of Ohio's 88 counties, with 112,634 people (2025 estimate). Its county seat is Troy. The map shows its 14 cities and towns and the 5 neighboring counties.
Miami County facts
- County seat
- Troy
- Population (2025 estimate)
- 112,634 +3.5% since 2020
- Land area
- 407 sq mi 70th largest of 88
- Water area
- 3 sq mi
- Population density
- 277 per sq mi
- Established
- 1807
- Named after
- Miami people Native American nation originally found in what is now Indiana, Michigan, and Ohio
- Largest city
- Troy 27,344
- Median household income
- $76,817
- Cities and towns
- 14 plus 1 CDPs
- ZIP codes
- 18
- Time zone
- Eastern
- FIPS code
- 39109
Cities and towns in Miami County
Miami County has 14 incorporated cities, towns and villages. Populations count the people living inside Miami County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Troy (county seat) | City | 27,344 | |
| Piqua | City | 21,064 | |
| Tipp City | City | 10,644 | |
| Huber Heights | City | 5,804 | Montgomery County |
| West Milton | Village | 4,871 | |
| Covington | Village | 2,635 | |
| Pleasant Hill | Village | 1,270 | |
| Bradford | Village | 1,085 | Darke County |
| Fletcher | Village | 469 | |
| Laura | Village | 412 | |
| Casstown | Village | 277 | |
| Potsdam | Village | 233 | |
| Ludlow Falls | Village | 178 | |
| Union | City | 43 | Montgomery County |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Brandt | 210 |
ZIP codes in Miami County
18 ZIP codes reach into Miami County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 45304 also Darke and Preble counties
- 45308 also Darke County
- 45309 also Montgomery, Darke and Preble counties
- 45312 also Champaign County
- 45317 also Champaign and Shelby counties
- 45318 also Darke County
- 45322 also Montgomery County
- 45326
- 45337 also Darke County
- 45339
- 45344 also Clark, Champaign and Montgomery counties
- 45356 also Shelby County
- 45359
- 45361
- 45371 also Montgomery County
- 45373
- 45383
- 45424 also Montgomery and Greene counties
Population of Miami County, 2020–2025
Miami County grew by 3,853 people (+3.5%) between April 2020 and July 2025: 872 more deaths than births and a net gain of 4,666 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 108,974 |
| 2021 | 109,392 |
| 2022 | 110,217 |
| 2023 | 110,925 |
| 2024 | 111,872 |
| 2025 | 112,634 |
Neighboring counties
- Montgomery County south · 539,598 people
- Shelby County north · 48,065 people
- Darke County west · 51,520 people
- Clark County east · 135,340 people
- Champaign County east · 38,820 people
Printable Miami 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) (103 KB)
- PNG (2400 px) (75 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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