Owsley County is a county located in the Eastern Coalfield region of the U.S. state of Kentucky. As of the 2020 census, the population was 4,051, making it the second-least populous county in Kentucky. The county seat is Booneville. The county was organized on January 23, 1843, from Clay, Estill, and Breathitt counties and named for William Owsley (1782–1862), the judge of the Kentucky Court of Appeals and Governor of Kentucky (1844–48). According to the 2010 census reports, Owsley County has the second-highest level of child poverty of any county in the United States. In terms of income per household, the county is the poorest in the nation. Between 1980 and 2014, the rate of death from cancer in the county increased by 45.6 percent, the largest such increase of any county in the United States.

William Owsley was an associate justice of the Kentucky Court of Appeals and the 16th Governor of Kentucky. He also served in both houses of the Kentucky General Assembly and was Kentucky Secretary of State under Governor James Turner Morehead.