From Ohio History Central
On January 16, 1807, the Ohio government authorized the creation of Miami County. Residents named the county in honor of the Miami Indians. Previously, the county had been part of Montgomery County.
Miami County is located in western Ohio. It is predominantly rural, with less than four percent of the county�s 407 square miles consisting of urban areas. The county seat is Troy. With a population of 21,999 people, Troy was the county�s largest community in 2000. Many residents of Ohio�s rural communities are seeking better lives and more opportunities in the state�s cities, but Miami County�s population grew between 1990 and 2000. The county experienced a 6.1 percent population growth rate between 1990 and 2000, bringing the total number of residents up to 98,868. The county averages 243 people per square mile.
Manufacturing businesses, retail positions, and service industries, such as health care and tourism, are Miami County�s largest employers. Farming ranks a distant fourth. In 1999, the per capita income in the county was 27,271 dollars, with seven percent of the people living in poverty.
Most voters in Miami County claim to be independents, yet in recent years, they have overwhelmingly supported Republican Party candidates at the national level.
American Indian agent John Johnston lived in Miami County, north of Piqua. The Ohio Historical Soceity maintains his farm, a portion of the Ohio and Erie Canal. and an Ohio Indian at the Piqua Historical Area.