[5] As of the census[11] of 2000, there were 8,080 people, 2,898 households, and 2,043 families living in the county.

There were 4,189 housing units at an average density of 19 per square mile (7.3/km2).

The racial makeup of the county was 91.86% White, 6.72% Black or African American, 0.30% Native American, 0.17% Asian, 0.01% Pacific Islander, 0.40% from other races, and 0.54% from two or more races.

The largest ancestry groups in Lyon County, Kentucky according to the census[11] of 2000 are: There were 2,898 households, out of which 25.10% had children under the age of 18 living with them, 59.80% were married couples living together, 8.10% had a female householder with no husband present, and 29.50% were non-families.

26.80% of all households were made up of individuals, and 12.20% had someone living alone who was 65 years of age or older.