Preble County is a county located in the U.S. state of Ohio. As of the 2020 census, the population was 40,999, down 3.0% from the 2010 census population of 42,270. Its county seat is Eaton. The county was formed on February 15, 1808, from portions of Butler and Montgomery Counties. It is named for Edward Preble, a naval officer who fought in the American Revolutionary War and against the Barbary Pirates.

Geography

According to the U.S. Census Bureau, the county has a total area of 426 sqmi, of which 424 sqmi is land and 2.3 sqmi (0.5%) is water.

Adjacent counties

Rivers and streams

Demographics

2020 census

As of the 2020 United States Census, there were 40,999 living in the county. The racial makeup of the county was 94.8% white, 0.5% black or African American, 0.2% American Indian, 0.4% Asian, 0.0% Pacific Islander, 0.4% from other races, and 3.7% from two or more races. Those of Hispanic or Latino ethnicity made up 0.9% of the population.

2010 census

As of the 2010 United States Census, there were 42,270 people, 16,341 households, and 11,867 families living in the county. The population density was 99.7 PD/sqmi. There were 17,888 housing units at an average density of 42.2 /mi2. The racial makeup of the county was 97.6% white, 0.4% black or African American, 0.4% Asian, 0.2% American Indian, 0.2% from other races, and 1.2% from two or more races. Those of Hispanic or Latino origin made up 0.6% of the population. In terms of ancestry, 34.3% were German, 14.6% were Irish, 12.7% were American, and 11.5% were English. Of the 16,341 households, 32.7% had children under the age of 18 living with them, 57.5% were married couples living together, 10.1% had a female householder with no husband present, 27.4% were non-families, and 23.2% of all households were made up of individuals. The average household size was 2.56 and the average family size was 2.99. The median age was 40.9 years. The median income for a household in the county was $49,780 and the median income for a family was $57,711. Males had a median income of $46,383 versus $30,876 for females. The per capita income for the county was $23,290. About 6.3% of families and 9.4% of the population were below the poverty line, including 13.1% of those under age 18 and 6.8% of those age 65 or over.

2000 census

As of the census of 2000, there were 42,337 people, 16,001 households, and 12,144 families living in the county. The population density was 100 PD/sqmi. There were 17,186 housing units at an average density of 40 /mi2. The racial makeup of the county was 98.47% White, 0.32% Black or African American, 0.21% Native American, 0.26% Asian, 0.02% Pacific Islander, 0.11% from other races, and 0.60% from two or more races. 0.43% of the population were Hispanic or Latino of any race. There were 16,001 households, out of which 34.20% had children under the age of 18 living with them, 63.50% were married couples living together, 8.50% had a female householder with no husband present, and 24.10% were non-families. 20.60% of all households were made up of individuals, and 8.90% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.02. In the county, the population was spread out, with 26.00% under the age of 18, 7.70% from 18 to 24, 28.70% from 25 to 44, 24.40% from 45 to 64, and 13.20% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 99.30 males. For every 100 females age 18 and over, there were 95.70 males. The median income for a household in the county was $42,093, and the median income for a family was $47,547. Males had a median income of $35,313 versus $23,573 for females. The per capita income for the county was $18,444. About 4.50% of families and 6.10% of the population were below the poverty line, including 7.00% of those under age 18 and 6.10% of those age 65 or over.

Politics

Preble County votes for Republicans more often than Democrats in presidential elections. It only supported a Democrat for president five times in the 20th century, the last being Lyndon Johnson in 1964. Jimmy Carter is the last Democrat to tally as much as 40 percent of the vote.

Education

Public school districts

School districts include:

Higher education

Communities

City

Villages

Townships

Census-designated place

Unincorporated communities

Notable residents