It is a dry county that prohibits the sale of alcoholic beverages, with the only exceptions being the Highland Winery and the city of Whitesburg, which voted on April 17, 2007, to allow the sale of alcoholic beverages in restaurants which seat at least one hundred people and obtain 70 percent of their revenue from food sales. In the city's first local-option election in more than sixty years, voters approved the measure by more than a 2-to-1 margin.
The killing of filmmaker Hugh O'Connor by a local landowner in 1967 brought Letcher County to national attention.
As of the census of 2000, there were 25,277 people, 10,085 households, and 7,462 families residing in the county. The population density was 75 per square mile (29 /km). There were 11,405 housing units at an average density of 34 per square mile (13 /km). The racial makeup of the county was 98.71% White, 0.51% Black or African American, 0.10% Native American, 0.28% Asian, 0.02% Pacific Islander, 0.03% from other races, and 0.35% from two or more races. 0.44% of the population were Hispanic or Latino of any race.
There were 10,085 households out of which 32.30% had children under the age of 18 living with them, 58.40% were married couples living together, 11.50% had a female householder with no husband present, and 26.00% were non-families. 24.10% of all households were made up of individuals and 10.10% had someone living alone who was 65 years of age or older. The average household size was 2.48 and the average family size was 2.94.
The age distribution was 23.70% under the age of 18, 9.20% from 18 to 24, 28.70% from 25 to 44, 25.80% from 45 to 64, and 12.60% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 95.80 males. For every 100 females age 18 and over, there were 92.10 males.
The median income for a household in the county was $21,110, and the median income for a family was $24,869. Males had a median income of $30,488 versus $17,902 for females. The per capita income for the county was $11,984. About 23.70% of families and 27.10% of the population were below the poverty line, including 35.90% of those under age 18 and 21.20% of those age 65 or over.