From Ohio History Central
On January 10, 1820, the Ohio government authorized the creation of Union County. The state formed the county from parts of Franklin, Delaware, Logan, and Madison Counties. Because the county was formed from a union of parts of other counties, residents chose the name Union for the new county.
Union County is located in west central Ohio. It is predominantly rural, with less than one percent of the county s 437 square miles consisting of urban areas. The county seat is Marysville. With a population of 15,942 people, Marysville was the county s largest community in 2000. Unlike most of Ohio s predominantly rural counties, Union County experienced an increase in population (twenty-eight percent) between 1990 and 2000, increasing the total number of residents to 40,909 people. The main reason for this increase was the large number of residents from Columbus, in nearby Franklin County, who sought to escape that city s busyness by moving to more rural, neighboring counties. Union County averages almost ninety-four people per square mile.
Manufacturing is the largest employer in Union County, followed by farming. Over seventy-three percent of the county s acreage is farmland. Service industries, such as health care and communications, and retail positions rank a distant third and fourth. Honda of America operates a plant in Marysville. This facility is the county s single largest employer. Marysville is also home for the Ohio State Reformatory for Women. In 1999, the per capita income in the county was 23,776 dollars, with 6.7 percent of the people living in poverty.
Most voters in Union County claim to be independents, yet in recent years, they have overwhelmingly supported Republican Party candidates at the national level.