County Named, 1806. For Colonel William Casey, early Ky. pioneer and great-grandfather of Samuel L. Clemens, "Mark Twain." Casey born in Va. Came to Ky. in 1779. Built Casey's Station on the Dix River in 1791. Member of Convention, 1799, to frame second Ky. Constitution. Trustee, town of Columbia, 1802. 1813, Presidential elector. Lived Adair Co., died, 1816. County formed from Lincoln.