Mercer County, Ohio
|Mercer County, Ohio|
Location in the state of Ohio
Ohio's location in the U.S.
|Founded||April 1, 1820|
|Named for||Hugh Mercer|
473.42 sq mi (1,226 km²)
462.45 sq mi (1,198 km²)
10.98 sq mi (28 km²), 2.32%
88.3/sq mi (34/km²)
|Time zone||Eastern: UTC-5/-4|
Mercer County is a county located in the state of Ohio, United States. According to the 2010 census, it has a population of 40,814, which is a decrease of 0.3% from 40,924 in 2000. Its county seat is Celina and is named for Hugh Mercer, an officer in the American Revolutionary War.
The Celina Micropolitan Statistical Area includes all of Mercer County.
History & Shape 
Mercer County was founded in 1820 which set it apart from Darke County. Land south of the Greenville Treaty Line was still part of Darke County. An act establishing Mercer County took place on January 2, 1824. In 1837 Van Wert County was detached and the county line established is the current northern border of Mercer County. In 1839 Celina was established as the capital of Mercer County, St. Marys, Ohio was the previous capital. In 1848 the area south of the Greenville Treaty Line to the current southern county line, was attached. When Auglaize County, Ohio was formed, Mercer County's eastern border was moved 6 miles west with the exception of the area south of the Greenville Treaty line. This created the sharp point at Mercer County's south-east corner and was the last county line modification.
According to the 2010 census, the county has a total area of 473.42 square miles (1,226.2 km2), of which 462.45 square miles (1,197.7 km2) (or 97.68%) is land and 10.98 square miles (28.4 km2) (or 2.32%) is water. The entire county has an elevation difference of less than 300 feet. The highest point is on the southern county line at 1071 feet above sea level. This is in very close proximity of the head waters for the Wabash River. The lowest point in the county is 780 feet above sea level. This point is located on the northern county line where the St. Marys River crosses over.
Drainage basins 
Mercer County has two rivers running through it; the Wabash and the St. Marys. The Wabash watershed is part of the Gulf of Mexico's watershed. The St. Marys watershed is part of Lake Erie's watershed. Creeks between these two watersheds are within a mile of each other at some places in Mercer County.
Beaver Creek 
Beaver Creek is the longest and largest creek in Mercer County. It stretches 19.7 miles and has two sections. The first section begins in southern farmland in the county and flows through the town of Montezuma, Ohio and into Grand Lake St. Marys. The other section of the creek begins as a spillway and empty's into the Wabash River. Beaver creek was originally one piece, but was split into two sections after the construction of Grand Lake. The creeks spillway, and last section, has been the subject of controversy and multimillion dollar lawsuits. Farmers along Beaver Creek claim their land floods because of the spillway that was put up in 1997, replacing the previous spillway that was built in 1913.
As of the census of 2010, there were 40,814 people, 14,756 households, and 11,022 families residing in the county. The population density was 88 people per square mile (34/km²). There were 15,875 housing units at an average density of 34 per square mile (13/km²). The racial makeup of the county was 98.44% White, 0.10% Black or African American, 0.26% Native American, 0.29% Asian, 0.02% Pacific Islander, 0.34% from other races, and 0.56% from two or more races. 1.15% of the population were Hispanic or Latino of any race.
There were 14,756 households out of which 37.10% had children under the age of 18 living with them, 64.10% were married couples living together, 7.40% had a female householder with no husband present, and 25.30% were non-families. 22.70% of all households were made up of individuals and 10.80% had someone living alone who was 65 years of age or older. The average household size was 2.74 and the average family size was 3.24.
In the county, the population was spread out with 29.60% under the age of 18, 7.90% from 18 to 24, 26.70% from 25 to 44, 21.20% from 45 to 64, and 14.50% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 99.80 males. For every 100 females age 18 and over, there were 96.20 males.
The median income for a household in the county was $42,742, and the median income for a family was $50,157. Males had a median income of $35,508 versus $22,857 for females. The per capita income for the county was $18,531. About 4.60% of families and 6.40% of the population were below the poverty line, including 6.90% of those under age 18 and 7.80% of those age 65 or over.
Unincorporated communities 
Adjacent counties 
- Van Wert County (north)
- Auglaize County (east)
- Shelby County (southeast) (at a single point)
- Darke County (south)
- Jay County, Indiana (southwest)
- Adams County, Indiana (northwest)
See also 
- "Ohio County Profiles: Mercer County" (PDF). Ohio Department of Development. Retrieved 2007-04-28.
- "Mercer County QuickFacts". United States Census Bureau. Retrieved 2012-02-16.
- "Find a County". National Association of Counties. Retrieved 2011-06-07.
- "Mercer County data". Ohio State University Extension Data Center. Retrieved 2007-04-28.[dead link]
- "Census 2010 U.S. Gazetteer Files: Counties". United States Census. Retrieved 2011-11-05.
- "American FactFinder". United States Census Bureau. Retrieved 2008-01-31.
||Adams County, Indiana||Van Wert County|
|Jay County, Indiana||Darke County||Shelby County|