As of the census² of 2000, there were 46,519 people, 18,820 households, and 13,399 families residing in the county. The population density was 33/km² (84/mi²). There were 20,668 housing units at an average density of 14/km² (38/mi²). The racial makeup of the county was 92.02% White, 6.21% Black or African American, 0.19% Native American, 0.34% Asian, 0.02% Pacific Islander, 0.37% from other races, and 0.86% from two or more races. 0.91% of the population were Hispanic or Latino of any race.

There were 18,820 households out of which 31.60% had children under the age of 18 living with them, 56.30% were married couples living together, 11.90% had a female householder with no husband present, and 28.80% were non-families. 25.80% 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 2.43 and the average family size was 2.91.

The median income for a household in the county was $30,868, and the median income for a family was $36,794. Males had a median income of $31,400 versus $20,014 for females. The per capita income for the county was $17,382. About 13.60% of families and 16.50% of the population were below the poverty line, including 24.40% of those under age 18 and 10.50% of those age 65 or over.

Neighboring areas include McLean County, Muhlenberg County, Christian County, Caldwell County, and Webster County. The cities and towns of Hopkins County are Charleston, Dawson Springs, Earlington, Hanson, Madisonville, Mortons Gap, Nebo,
Nortonville, St. Charles, White Plains, and Manitou.