Many member family trees on Ancestry.com identify the John McClain and James McClain who settled in Bath Co., Ky as sons of Charles McClain and Elizabeth Moon of North and South Carolina. I have not seen any primary sources for that attribution (e.g., none of the trees mention any wills, etc.), so I prefer to consider their parents unknown.

In 1870 he is listed with his daughter Sarah and her husband William Staton as age 77, wheel wright, born in Kentucky.

In 1880 he is listed with them as John McClane, age 88, border, wheelrite, born S.C. S.C. Vct. (I do not know how to interpret the Vct, but it is entered for several other parent birthplace fields on the page. I suspect it of being an abbreviation for unstated, in some form.)

1850 census of Bath Co., Ky, division 2, enumerated 27 July, lists on p. 26 as family #181:
John McClane, 58, wheelright, b. S. Carolina; Micha, 34, b. Ky; Amanda, 11; Jenelly (f), 9; Isaac, 7; Sousan Jackson, 7; Alfred, 5; Joseph, 4; Garrard McLane, 9/12. All children born in Kentucky.

All of the McClane children except Garrard are from John’s second marriage, to Nancy Richardson.