Possibly a brother of Isaac Newton Hardin born ca 1836, since they are two years apart in age and both living in households other than their parents in the 1850 Morgan Co. census (Jackson with John Cassity and Elizabeth Brown; Isaac Newton with Isaac Hardin Sr. and Nancy Crose.) One pair of candidates for their parents are Samuel Hardin and Patsy Brown who were married 23 Feb 1825 in Morgan Co. by Samuel Jackson. Theirs is the only other early Hardin marriage in Morgan Co. besides the marriage of Isaac Hardin & Nancy Crose in 1836, and the Brown connection could account for Jackson living with John Cassity & Elizabeth Brown. (There is no Hardin/Cassity marriage recorded in Morgan Co.)

This is not proof, though; it could be that Jackson’s parents were married in a different county.

1850 census of Morgan Co., Ky, lists Jackson Hardin, age 16, living in household #107 with the family of John and Elizabeth Cassity. See their census notes for details.

Morgan Co., Ky birth records list Lydia Perry, born 22 May 1856, father Thomas Perry Jr., mother’s maiden name Isabel Caskey.

Her death certificate lists Lidy Harden, age 55, born 1859 in Morgan Co., died 25 Apr 1914 in Morgan Co., widowed, father Thomas Perry, mother’s maiden name Isabell Cakey, both born in Morgan Co., cause of death unknown, informant J. F. Perry, Wrigley, Ky.

Morgan Co. marriage records list the marriage of A. J. Hardin and Lydia Perry on 23 Dec 1879, at Thomas Perry’s by Elijah Hicks, witnesses I. N. Hardin and Thomas Perry.

1880 census of Morgan Co., Ky, North Fork precinct, enumerated 3 June, lists on p. 5 as family #39:
Perry, Thomas, 48, farmer; Isabelle, 47, wife; James M., 21, son; Mary M., 17, dau; Huldah J., 14, dau; Matilda A., 7, dau; Everet, 5, son; Hardin, Andrew J., 43, son-in-law; Lydia, 22, dau. All born Ky Ky Ky.

1900 census of Morgan Co., Ky, district 6, enumerated 16 June, lists on p. x as family #231/232:
Hardin, Andrew J., farmer, 65, b. Mar 1835; Lydia, wife, 40, b. May 1860, married 19 years, mother of 2 children, 2 living; Martha B., dau, 19, b. Feb 1881, single, mother of 1 child, 1 living; Nanna, dau, 17, b. July 1882; Carmie L., granddau, 2, b. Dec 1897. All born Ky Ky Ky.

1910 census of Morgan Co., Ky, Panthers Branch precinct, enumerated 18 April, lists on p. 2B as family #35:
Hardin, Lyda, 52, widowed, mother of 2 children, 2 living; Martha B., dau, 28, single; Carma, granddau, 12; Asia, grandson, 9; Dewey, grandson, 7; Bob, grandson, 5; Clayton, grandson, 4; Willie, grandson, 2. All born Ky Ky Ky.