U.S. Decennial Census 1850-2010 2012 Estimate
As of the census of 2000, there were 97,589 people, 51,265 households, and 22,150 families residing in the county. The population density was 144 people per square mile (56/km²). There were 55,643 housing units at an average density of 53 per square mile (20/km²). The racial makeup of the county was 78.92% White, 3.68% Black or African American, 0.69% Native American, 0.79% Asian, 0.07% Pacific Islander, 13.36% from other races, and 2.49% from two or more races. 29.57% of the population were Hispanic or Latino of any race. There were 33,410 households out of which 34.00% had children under the age of 18 living with them, 53.10% were married couples living together, 9.00% had a female householder with no husband present, and 33.70% were non-families. 21.00% of all households were made up of individuals and 4.90% had someone living alone who was 65 years of age or older. The average household size was 2.69 and the average family size was 3.21.
In the county, the population was spread out with 24.50% under the age of 18, 20.50% from 18 to 24, 28.20% from 25 to 44, 19.10% from 45 to 64, and 7.70% who were 65 years of age or older. The median age was 28 years. For every 100 females there were 101.30 males. For every 100 females age 18 and over, there were 99.50 males.
The median income for a household in the county was $45,006, and the median income for a family was $56,287. Males had a median income of $35,209 versus $27,334 for females. The per capita income for the county was $19,931. About 6.40% of families and 14.30% of the population were below the poverty line, including 10.30% of those under age 18 and 9.70% of those age 65 or over.
Higher education in Hays County includes one four-year institution, Texas State University, which is located in San Marcos. There are three Distance Learning Centers that are operated by Austin Community College. These centers offer basic and Early College Start classes along with testing centers for online classes.