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Ohio Counties

There is eighty-eight counties in the state of Ohio. Washington County the oldest in the state established on July 27, 1788. Noble County was formed on March 11, 1851 from portions of Guernsey, Morgan, Monroe and Washington counties. It was the last county to be formed in Ohio and, therefore, represents the youngest county in the state.

Seneca County, Ohio

Seneca County Education, Geography, and HistorySeneca County, Ohio Courthouse

Seneca County is a county located in the state of Ohio. Based on the 2010 census, the population was 56,745. Its county seat is Tiffin. The county was created in 1820 and later organized in 1824. It is named for the Seneca Indians.

Seneca County comprises the Tiffin, OH Micropolitan Statistical Area, which is also included in the Findlay-Tiffin, OH Combined Statistical Area.

Etymology - Origin of Seneca County Name

Residents named the county after the Seneca Indian tribe.


County QuickFacts: CensusBureau Quick Facts

Seneca County History

On February 12, 1820, the Ohio government authorized the creation of Seneca County. Residents named the county after the Seneca Indian tribe. Seneca County was originally part of territory set aside for Ohio's Indian people by the Treaty of Greeneville. White settlement of the county occurred slowly, due to the Great Black Swamp occupying some of the land.

Seneca County is located in the northern part of Ohio. The county seat is Tiffin, which is the largest city in the county with a population of 18,135 people in 2000. Only 1.4 percent of the county's 151 square miles are deemed to be urban. The county averages almost 107 people living in each square mile. Between 1990 and 2000, the county experienced a slight decrease in population. This is typical of Ohio's more rural counties, as residents seek better opportunities in the state's larger cities. In 2000, the county's residents numbered 58,683 people.

Most of Seneca County's residents find employment in manufacturing businesses, service industries, and retail positions. Over 1,300 farms also exist in the county. During the late nineteenth and early twentieth centuries, the county's natural gas deposits led to a booming glass-making industry. Residents produced glass for both Fostoria and Tiffin. In 1999, the county's per capita income was 21,695 dollars, with 9.6 percent of the county's residents living below the poverty level.

Most voters in Seneca County claim to be independents, yet in recent years, they have supported Republican Party candidates at the national level.

The county is home to Heidelberg College.

Seneca County, Ohio History Central, July 24, 2008,

Geography: Land and Water

As reported by the Census Bureau, the county has a total area of 553 square miles (1,430 km2), of which 551 square miles (1,430 km2) is land and 1.8 square miles (4.7 km2) (0.3%) is water.

Almost 80% of the county's total area is agricultural land. Some 10% is covered by forest, and the rest is mostly taken up by built-up areas and to a slightly lesser extent by pastureland.

The terrain of Seneca County is nearly level, gently sloping from about 290 meters ASL in the southeast to about 210 m ASL at the edge of the erstwhile Great Black Swamp in the northwest. Most of the county's area is located between 230 and 260 m ASL however. Almost the entire county belongs to the Sandusky River drainage basin; the river itself bisects the county from north to south slightly west of its middle, running through Tiffin as it does so. There is some steeper terrain along the rivers's course, formed by the occasional ravine of its tributaries.

Neighboring Counties

Bordering counties are as follows:

  • Sandusky County (north)
  • Huron County (east)
  • Crawford County (southeast)
  • Wyandot County (southwest)
  • Hancock County (west)
  • Wood County (northwest)


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