As of the census of 2000, there were 15,657 people, 5,663 households, and 4,150 families residing in the county. The population density was 25 people per square mile (10/km²). There were 6,851 housing units at an average density of 11 per square mile (4/km²). The racial makeup of the county was 76.59% White, 12.08% Black or African American, 0.46% Native American, 0.24% Asian, 0.03% Pacific Islander, 8.87% from other races, and 1.72% from two or more races. 18.19% of the population were Hispanic or Latino of any race. 35.5% were of German and 8.3% American ancestry according to Census 2000. 80.1% spoke English, 14.4% Spanish and 5.1% German as their first language.
There were 5,663 households out of which 35.70% had children under the age of 18 living with them, 60.00% were married couples living together, 8.80% had a female householder with no husband present, and 26.70% were non-families. 23.80% of all households were made up of individuals and 11.70% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.15.
In the county, the population was spread out with 28.80% under the age of 18, 9.20% from 18 to 24, 26.30% from 25 to 44, 21.40% from 45 to 64, and 14.40% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 101.60 males. For every 100 females age 18 and over, there were 98.00 males.
The median income for a household in the county was $36,280, and the median income for a family was $42,073. Males had a median income of $30,635 versus $21,611 for females. The per capita income for the county was $17,163. About 9.70% of families and 11.90% of the population were below the poverty line, including 13.70% of those under age 18 and 16.10% of those age 65 or over.