According to the U.S. Census Bureau, the county has a total area of 2,215 km² (855 mi²). 2,204 km² (851 mi²) of it is land and 11 km² (4 mi²) of it is water. The total area is 0.50% water.
As of the census2 of 2000, there are 35,935 people, 13,691 households, and 8,639 families residing in the county. The population density is 16/km² (42/mi²). There are 14,757 housing units at an average density of 7/km² (17/mi²). The racial makeup of the county is 83.27% White, 2.27% Black or African American, 0.47% Native American, 2.04% Asian, 0.01% Pacific Islander, 9.79% from other races, and 2.16% from two or more races. 16.72% of the population are Hispanic or Latino of any race.
There are 13,691 households out of which 32.60% have children under the age of 18 living with them, 50.80% are married couples living together, 8.40% have a female householder with no husband present, and 36.90% are non-families. 28.50% of all households are made up of individuals and 9.80% have someone living alone who is 65 years of age or older. The average household size is 2.51 and the average family size is 3.12.
In the county the population is spread out with 25.70% under the age of 18, 16.20% from 18 to 24, 27.20% from 25 to 44, 19.10% from 45 to 64, and 11.60% who are 65 years of age or older. The median age is 31 years. For every 100 females there are 97.40 males. For every 100 females age 18 and over, there are 95.20 males.
The median income for a household in the county is $32,819, and the median income for a family is $43,112. Males have a median income of $28,865 versus $21,338 for females. The per capita income for the county is $15,724. 14.50% of the population and 9.60% of families are below the poverty line. Out of the total people living in poverty, 15.60% are under the age of 18 and 9.20% are 65 or older.