Hi , I have a book, Jarnagin Collection and Allied Families, to which my grandmother and her sister provided much information to the author Glenn Susong Clark. It begins with Thomas Jarnagin and Mary Witt. There is just a short sentence about Thomas' parents:
"Thomas Jarnagin, son of (Col.) John and Mary (Bynum) Jarnagin, was born on July 26, 1746 in Virginia. [The exact place has not been proven, but it is believed to be in Virginia, a few miles from Annapolis, Md.] He died at Mt. Harmony, on Long Creek, Jefferson County, Tennessee, on February 26, 1802. In 1767 he married Mary Witt, daughter of Charles and Lavinia (Harbour) Witt of Hallifax County, Va. She was born in Hallifax County on April 4, 1753. She died at Mt. Harmony on Monday, August 6, 1829. Both are buried in unmarked graves in the Mt. Harmony Jarnagin Cemetery.
Thomas had a brother, John, who married Mary Smith. His death year is recorded as 1816. Here is some more text about him:
"John Jarnagin, Senr. [he is referred to as Senr. in the 1797 minutes of Grainger co., Tenn. Court Records] came from the Danville, Virginia region. The exact period of his migration from Virginia to the East Tennessee region has not been established. ...
It goes on to say:
"John Jarnagin was possibly over 60 years of age when he moved from Grainger County, Tennessee to Highland County, Ohio.
So the John in Ohio was the son of John and Mary (Bynum) Jarnagin.
Also, I would venture to say that Thomas' middle name was probably Bynum.