Washington County is a county located in the U.S. state of Illinois. According to the 2010 census, it had a population of 14,716. Its county seat is Nashville. It is located in the southern portion of Illinois known locally as “Little Egypt”.
According to the U.S. Census Bureau, the county has a total area of 564 square miles (1,460 km), of which 563 square miles (1,460 km) is land and 1.3 square miles (3.4 km) (0.2%) is water. There are many lakes, rivers, streams, and creeks in this area, including the Kaskaskia River, which is the county’s northern border.
As of the 2010 United States Census, there were 14,716 people, 5,926 households, and 4,112 families residing in the county. The population density was 26.2 inhabitants per square mile (10.1/km). There were 6,534 housing units at an average density of 11.6 per square mile (4.5/km). The racial makeup of the county was 97.7% white, 0.7% black or African American, 0.3% Asian, 0.1% American Indian, 0.4% from other races, and 0.8% from two or more races. Those of Hispanic or Latino origin made up 1.3% of the population. In terms of ancestry, 53.6% were German, 14.0% were Polish, 13.1% were Irish, 7.7% were English, and 6.1% were American.
Of the 5,926 households, 30.1% had children under the age of 18 living with them, 57.6% were married couples living together, 7.3% had a female householder with no husband present, 30.6% were non-families, and 25.9% of all households were made up of individuals. The average household size was 2.44 and the average family size was 2.93. The median age was 42.3 years.
The median income for a household in the county was $51,440 and the median income for a family was $64,171. Males had a median income of $44,272 versus $30,683 for females. The per capita income for the county was $24,846. About 5.5% of families and 9.1% of the population were below the poverty line, including 13.2% of those under age 18 and 8.9% of those age 65 or over.