Greene County is a county located in the U.S. state of Missouri. As of the 2010 census, its population was 275,174, making it the fourth most-populous county in Missouri. Its county seat and most-populous city is Springfield. The county was organized in 1833 and is named after American Revolutionary War General Nathanael Greene.
According to the U.S. Census Bureau, the county has a total area of 678 square miles (1,760 km), of which 675 square miles (1,750 km) is land and 2.6 square miles (6.7 km) (0.4%) is water.
As of the census of 2000, there were 240,391 people, 97,859 households, and 61,846 families residing in the county. The population density was 356 people per square mile (138/km²). There were 104,517 housing units at an average density of 155 per square mile (60/km²). The racial makeup of the county was 93.54% White, 2.26% Black or African American, 0.66% Native American, 1.13% Asian, 0.06% Pacific Islander, 0.67% from other races, and 1.68% from two or more races. Approximately 1.84% of the population were Hispanic or Latino of any race.
There were 97,859 households out of which 28.30% had children under the age of 18 living with them, 50.00% were married couples living together, 9.80% had a female householder with no husband present, and 36.80% were non-families. 29.10% of all households were made up of individuals and 9.70% had someone living alone who was 65 years of age or older. The average household size was 2.34 and the average family size was 2.89.
In the county, the population was spread out with 22.30% under the age of 18, 13.80% from 18 to 24, 28.60% from 25 to 44, 21.80% from 45 to 64, and 13.60% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 94.40 males. For every 100 females age 18 and over, there were 91.20 males.
The median income for a household in the county was $44,185, and the median income for a family was $56,047. Males had a median income of $30,672 versus $21,987 for females. The per capita income for the county was $25,770. About 7.60% of families and 12.10% of the population were below the poverty line, including 13.60% of those under age 18 and 7.50% of those age 65 or over.
There are 190,417 registered voters in Greene County.