Demographics
As of the census of 2000, there were 23,590 people, 8,747 households, and 6,481 families residing in the county. The population density was 14/km² (36/sq mi). There were 10,205 housing units at an average density of 6/km² (16/sq mi). The racial makeup of the county was 80.22% White, 10.64% Black or African American, 0.28% Native American, 0.29% Asian, 6.99% from other races, and 1.58% from two or more races. 16.13% of the population were Hispanic or Latino of any race.

There were 8,747 households out of which 34.70% had children under the age of 18 living with them, 60.60% were married couples living together, 9.60% had a female householder with no husband present, and 25.90% were non-families. 22.80% of all households were made up of individuals and 11.50% had someone living alone who was 65 years of age or older. The average household size was 2.67 and the average family size was 3.14.

In the county, the population was spread out with 27.00% under the age of 18, 8.10% from 18 to 24, 26.40% from 25 to 44, 23.70% from 45 to 64, and 14.80% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 96.50 males. For every 100 females age 18 and over, there were 92.90 males.

The median income for a household in the county was $38,615, and the median income for a family was $46,342. Males had a median income of $32,455 versus $22,142 for females. The per capita income for the county was $18,140. About 8.80% of families and 12.10% of the population were below the poverty line, including 13.70% of those under age 18 and 14.40% of those age 65 or over.

Education
The following school districts serve Austin County:

• Bellville Independent School District
• Brazos Independent School District (partial)
• Brenham Independent School District (partial)
• Columbus Independent School District (partial)
• Sealy Independent School District

Cities and Towns

• Bellville
• Brazos Country
• Industry
• Sealy
• Wallis
• San Felipe
• Shelby