Casey County was established on November 14, 1806 and named in honor of Revolutionary War veteran, and great-grandfather of Mark Twain, Col. William Casey. One of the first families to settle in Casey County was that of Captain Abraham Lincoln, the president's grandfather. The family lived for two and a half years on 800 acres on the Green River. While there is no record of Civil War battles taking place in Casey County, the county is credited with producing one-third of the 1st Kentucky Cavalry which served in the Union army. The 1st Cavalry was active in the Battles of Mill Springs, Perryville, and Lebanon, Tennessee.

Today Casey County is known for its annual apple festival held every September, its Amish and Mennonite communities and the Central Kentucky Ag/Expo Center.