Miami County is a county in Ohio, United States, on the Great Miami River between Dayton and Sidney. It had a population of 108,774 at the 2020 census and covers 410 square miles (1,100 km2), of which 407 square miles (1,050 km2) are land and 3.1 square miles (8.0 km2) are water, centred near 40°03′N 84°14′W.
Troy is the county seat, and its postal code is 45373. The county has three cities (Troy, Piqua and Tipp City), eight villages and about a dozen unincorporated communities, grouped across twelve townships. Miami County is part of the Dayton metropolitan area and sits in the Eastern time zone.
Towns & Villages in Miami County
Miami County has three cities and eight incorporated villages, plus a scatter of unincorporated crossroads communities that carry their own ZIP codes or historical names. “CDP” marks a Census Bureau-defined place with no incorporated government; “Unincorp.” marks a named community with no incorporation and no separate 2020 count.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Troy | City · seat | Concord | — | 45373 |
| Piqua | City | Washington | — | 45356 |
| Tipp City | City | Monroe | — | 45371 |
| Bradford | Village | Newberry | — | 45308 |
| Casstown | Village | Lostcreek | — | 45312 |
| Conover | Village | Newton | — | 45317 |
| Covington | Village | Newberry | — | 45318 |
| Fletcher | Village | Newton | — | 45326 |
| Laura | Village | — | — | 45337 |
| Ludlow Falls | Village | Newton | — | 45339 |
| Pleasant Hill | Village | Newton | — | 45359 |
| Potsdam | Village | Newberry | — | 45361 |
| West Milton | Village | Union | — | 45383 |
| Staunton | Unincorp. | Staunton | — | 45373 |
| West Charleston | Unincorp. | Bethel | — | — |
| Phoneton | Unincorp. | Bethel | — | — |
| Alcony | Unincorp. | Newton | — | — |
| Eldean | Unincorp. | Concord | — | — |
| Frederick | Unincorp. | Elizabeth | — | — |
| Lena | Unincorp. | Elizabeth | — | — |
| Rossville | Unincorp. | Washington | — | 45356 |
Some place names near the county line overlap with neighboring counties. Huber Heights and Union sit mostly in Montgomery County, with only a small edge inside Miami County, so neither is listed here as a Miami County place.
Townships
Miami County has twelve civil townships. 2020 township-level population figures are not independently verified here, so they are omitted rather than estimated.
| Township | Pop. (2020) | Main settlements |
|---|---|---|
| Concord | — | Troy, Eldean |
| Washington | — | Piqua, Rossville |
| Monroe | — | Tipp City |
| Union | — | West Milton |
| Newton | — | Fletcher, Pleasant Hill, Ludlow Falls, Alcony |
| Newberry | — | Covington, Bradford, Potsdam |
| Bethel | — | West Charleston, Phoneton |
| Elizabeth | — | Frederick, Lena |
| Lostcreek | — | Casstown |
| Staunton | — | Staunton |
| Brown | — | rural, no incorporated place |
| Spring Creek | — | rural, no incorporated place |
ZIP Codes
- 45373 — Troy (also serves Staunton)
- 45356 — Piqua (also serves Rossville)
- 45371 — Tipp City
- 45383 — West Milton
- 45318 — Covington
- 45308 — Bradford
- 45359 — Pleasant Hill
- 45337 — Laura
- 45326 — Fletcher
- 45317 — Conover
- 45312 — Casstown
- 45339 — Ludlow Falls
- 45361 — Potsdam
Troy also carries the single-entity ZIP 45374 for certain large mail recipients. Smaller unincorporated communities such as West Charleston, Phoneton, Alcony, Eldean, Frederick and Lena share the ZIP of their nearest post office town rather than having their own.
Geography
Miami County sits in west-central Ohio on the till plains, drained by the Great Miami River, which runs south through Piqua, Troy and Tipp City on its way to Dayton. Stillwater River and Loramie Creek are the other principal waterways, and the terrain is mostly flat to gently rolling farmland with wooded floodplain along the rivers. Miami County borders Shelby County to the north, Champaign County to the northeast, Clark County to the southeast, Montgomery County to the south, and Darke County to the west. Shelby and Champaign counties do not currently have their own pages on this site.
Demographics
Miami County had 108,774 residents at the 2020 census. Troy and Piqua are its two largest communities by a wide margin, together holding roughly half the county’s population. Median household income in the county runs close to the Ohio median of $67,769, with Troy and Tipp City somewhat above that figure and rural townships somewhat below. Density works out to about 267 people per square mile across the county’s 407 land square miles.
Economy & Local Life
Manufacturing remains the backbone of the county economy, anchored by Piqua’s industrial base and Troy’s cluster of automotive-parts and packaging plants, including a longtime Hobart Brothers welding-products operation in Troy. Edison State Community College, headquartered in Piqua, serves the county and the wider region. Agriculture — corn and soybeans on the till-plain farmland — still dominates the townships outside the three cities. Troy’s Troy Strawberry Festival, held every June, is the county’s best-known annual event and draws visitors from across the Miami Valley.
History
Miami County was organized on March 1, 1807, carved from Montgomery County, and takes its name from the Miami people, whose territory once covered this stretch of the Great Miami River valley. Troy was platted as the county seat the same year. Piqua grew around a earlier Shawnee town site and became a canal-era manufacturing center after the Miami and Erie Canal reached it in the 1830s, a period that also built up Troy and several of the county’s smaller river towns.
Getting There
Interstate 75 runs the length of the county north–south, with Ohio Route 55 and Ohio Route 41 providing the main east–west connections through Troy and Piqua.
- Dayton — 20 miles south
- Sidney — 15 miles north
- Springfield — 25 miles east
- Columbus — 65 miles east
Dayton International Airport, just south of the county line, is the nearest commercial airport.
Frequently Asked Questions
Where is Miami County, Ohio?
It is in west-central Ohio, on the Great Miami River between Dayton and Sidney, part of the Dayton metropolitan area.
What is the population of Miami County?
108,774 people, per the 2020 census.
How big is Miami County?
410 square miles (1,100 km2) in total, of which 407 square miles are land.
What is the county seat of Miami County?
Troy is the county seat.
How many towns are in Miami County?
Three cities — Troy, Piqua and Tipp City — and eight incorporated villages, plus several smaller unincorporated communities.
What ZIP codes are in Miami County?
Thirteen standard ZIP codes, from 45373 (Troy) and 45356 (Piqua) to smaller village codes like 45326 (Fletcher) and 45361 (Potsdam).
What is Miami County known for?
Troy’s annual Strawberry Festival, its Great Miami River valley farmland, and a manufacturing base built up during the canal era in Troy and Piqua.
More counties in this state: Towns and villages in Ohio.