Zach and Cath - John was born ca. 1750, Bucks Co., Pa. He died 1806 inn Stubenville, Jefferson County,Ohio. His wife was Margaret (unknown), and she died 1817 in Stubenville.
John was born before Tuscawarus county and before the state of Ohio was formed. Source= Barnhill - Speer family history. Leonard Loren Barnhill referred to this John as "North Carolina Barnhill" in error. John lived in Jefferson and Harrison Counties, Ohio. Christian name of spouse may have been Margaret. Interesting to note the will of John Barnhill dated 28 December 1805 was witnessed by James Barnhill. I have not been able thus far to determine who this James Barnhill is. UPDATE 2010: Dorothy Williams Potter of Birmingham, Alabama in her "Ancestral Anthology" series, Volume I, beginning PP. 70 identifies this John as one of the two immigrant siblings who died in Jefferson County, Ohio in 1806. If correct, then James would be his brother. Dorothy Potter is recognized as probably the leading authority in modern Barnhill research, and if she is correct, my analysis regarding the parentage of John and James is in error.
John and Martha had 4 children (to my knowledge). They were, Jenny (b. 1790); Robert (b. 1796; Mary (b. 1799); and Hugh (b. 1806). Happy hunting. ~Stan~