Bourbon County is part of the Lexington–Fayette Metropolitan Statistical Area.
As of the census of 2000, there were 19,360 people, 7,681 households, and 5,445 families residing in the county. The population density was 66 per square mile (25 /km). There were 8,349 housing units at an average density of 29 per square mile (11 /km). The racial makeup of the county was 90.38% White, 6.94% Black or African American, 0.15% Native American, 0.14% Asian, 0.01% Pacific Islander, 1.36% from other races, and 1.02% from two or more races. 2.60% of the population were Hispanic or Latino of any race.
There were 7,681 households out of which 32.80% had children under the age of 18 living with them, 54.70% were married couples living together, 12.30% had a female householder with no husband present, and 29.10% were non-families. 24.80% of all households were made up of individuals and 11.10% had someone living alone who was 65 years of age or older. The average household size was 2.49 and the average family size was 2.95.
In the county the population was spread out with 25.00% under the age of 18, 8.10% from 18 to 24, 28.60% from 25 to 44, 24.70% from 45 to 64, and 13.60% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 94.60 males. For every 100 females age 18 and over, there were 91.00 males.
The median income for a household in the county was $35,038, and the median income for a family was $42,294. Males had a median income of $30,989 versus $23,467 for females. The per capita income for the county was $18,335. About 12.30% of families and 14.00% of the population were below the poverty line, including 19.10% of those under age 18 and 11.90% of those age 65 or over.