Miami County, Ohio

Miami County
County courthouse in Troy
Location within the U.S. state of Ohio
Ohio's location within the U.S.
Coordinates: 40°03′N 84°14′W / 40.05°N 84.23°W / 40.05; -84.23
Country United States
State Ohio
FoundedMarch 1, 1807
Named afterMiami people
SeatTroy
Largest cityTroy*
Area
  Total
410 sq mi (1,100 km2)
  Land407 sq mi (1,050 km2)
  Water3.1 sq mi (8 km2)  0.8%
Population
 (2020)
  Total
108,774
Time zoneUTC−5 (Eastern)
  Summer (DST)UTC−4 (EDT)
Congressional districts8th, 15th
Websitewww.miamicountyohio.gov

Miami County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 108,774. Its county seat is Troy. The county is named in honor of the Miami people. Miami County is part of the Dayton, OH Metropolitan Statistical Area.