According to the U.S. Census Bureau, the county has a total area of 821 km² (317 mi²). 820 km² (317 mi²) of it is land and 1 km² (0 mi²) of it is water. The total area is 0.12% water.
As of the census2 of 2000, there are 41,624 people, 13,178 households, and 9,211 families residing in the county. The population density is 51/km² (131/mi²). There are 14,684 housing units at an average density of 18/km² (46/mi²). The racial makeup of the county is 90.08% White, 6.91% Black or African American, 0.16% Native American, 1.06% Asian, 0.04% Pacific Islander, 0.37% from other races, and 1.37% from two or more races. 3.90% of the population are Hispanic or Latino of any race.
There are 13,178 households out of which 31.10% have children under the age of 18 living with them, 59.90% are married couples living together, 6.90% have a female householder with no husband present, and 30.10% are non-families. 25.30% of all households are made up of individuals and 11.80% have someone living alone who is 65 years of age or older. The average household size is 2.50 and the average family size is 3.00.
In the county, the population is spread out with 20.10% under the age of 18, 13.90% from 18 to 24, 30.90% from 25 to 44, 21.70% from 45 to 64, and 13.40% who are 65 years of age or older. The median age is 36 years. For every 100 females there are 123.90 males. For every 100 females age 18 and over, there are 128.50 males.