Posey County is part of the Evansville, IN–KY Metropolitan Statistical Area.
2000 27,061 1990 25,968 1980 26,414 1970 21,740 1960 19,214 1950 19,818 1940 19,183 1930 17,853 1920 19,334 1910 21,670 1900 22,333 1890 21,529 1880 20,857 1870 19,185 1860 16,167 1850 12,549 1840 9,683 1830 6,549 1820 4,061
As of the census of 2000, there were 27,061 people, 10,205 households, and 7,612 families residing in the county. The population density was 66 people per square mile (26/km²). There were 11,076 housing units at an average density of 27 per square mile (10/km²). The racial makeup of the county was 97.97% White, 0.86% Black or African American, 0.27% Native American, 0.16% Asian, 0.16% from other races, and 0.58% from two or more races. 0.44% of the population were Hispanic or Latino of any race. 44.2% were of German, 19.2% American, 10.8% English and 7.0% Irish ancestry according to Census 2000.
There were 10,205 households out of which 36.40% had children under the age of 18 living with them, 63.50% were married couples living together, 7.80% had a female householder with no husband present, and 25.40% were non-families. 22.10% of all households were made up of individuals and 10.00% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 3.08.
In the county the population was spread out with 27.30% under the age of 18, 7.40% from 18 to 24, 29.00% from 25 to 44, 23.90% from 45 to 64, and 12.40% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 99.10 males. For every 100 females age 18 and over, there were 96.30 males.
The median income for a household in the county was $44,209, and the median income for a family was $53,737. Males had a median income of $39,084 versus $23,996 for females. The per capita income for the county was $19,516. About 6.00% of families and 7.40% of the population were below the poverty line, including 8.50% of those under age 18 and 10.00% of those age 65 or over.