Allen line: Will our John Campbell please stand up and identify himself?

The known facts about John Campbell are few and far between.  We know he died in Madison County, Kentucky, on April 20, 1806 and is buried in Madison County, Kentucky.  This John Campbell is most probably "our" John Campbell, because he was married to Jane Garvin and in 1809 we have a copy of Jane G Campbell giving permission for her daughter, Sarah, also known as "Sally", to marry Lemuel Dunn in Madison County, Ky. 

There was a John Campbell who was the witness of his brother Thomas's will in Madison County, Ky on May 17, 1796.  We don't know if this is the same John Campbell, because Campbell was a common name in Kentucky at that time, and even in Madison County there seem to be several families of Campbell.  There was a John Campbell listed in the Madison County Tax list of 1800.  On that list, he is named as "John A."  Is this a correct initial for our John?  What might it signify? There is also a John Campbell who was a witness to the will of William Hamilton on June 28, 1800 in Madison County, Kentucky.  Again, is this one ours, or someone else's?

A transcript of information, or more precisely, a query, was printed in the Boston Transcript on January 14, 1929.  "Wanted, parents of John Campbell born in Pa in about 1760, married Jane Garvin born in Ireland abt 1763. They were married about 1784, and had John G, born January 22, 1785, Mary Powers, born December 22, 1786, Sarah Reid born November 22, 1788, Isaac, born March 19, 1797, and David Garvin, born October 2, 1799.  The younger members of the family were born near Union, Monroe County, WV.  They emigrated to Kentucky 1802-1805, settled in Mercer County.  John Campbell died April 20, 1806 and is buried in Madison County, Kentucky.  He had a brother, Hugh, and I do not know names of other children of this family.  Would like this information. H.M." 

There were Garvins in Madison County, Ky during this same time period, and also in Monroe/Greenbrier County, WV a decade earlier.  If we trace Garvins back further, they can be found in Cumberland County, Pa., as can several families of Campbells.  This may be a possible clue. However, there are also a large number of Campbells in Augusta County, Va,, who may somehow be connected. To complicate matters, a biography of George Washington Dunn, son of Lemuel Dunn and Sarah Reid Campbell,  indicates that John Campbell fought in the Revolutionary War from Virginia.  There are too many pieces to this puzzle; some have to belong to some other family.  The question is, which ones?

Well, H.M., I would certainly like to have the answers to your query, also.  I can find hints and bits and pieces of two or possibly three John Campbell families in Monroe/Greenbriar County, WV and in Augusta County, Va, but nothing that would rule one of the families in or out.  Then there is a list of taxables from 1792 in Washington County, Virginia that includes the names of Hugh, James, John, and Thomas, (also Anne Campbell) which should probably be pursued, since John's brothers were Hugh and possibly Thomas, and there was a James Campbell in Mercer County, Ky (where Sarah Campbell Dunn lived) in 1830 who would have been the right age to be the brother of John and possibly Thomas and Hugh.  There are so many clues, but my puzzle just isn't taking shape yet.   

I'm reasonably sure that John is going to trace back somehow to one of the Campbells of Scotland, but I don't know if it will be ever be possible to make that connection.  For now, I'd just be excited to find out whether he came from Cumberland County, Pa, or August County, Va, or Washington County, Va, or some other location entirely, and I'd be thrilled to know who his parents were! 

Here's the line of descent:

John Campbell-Jane Garvin
Sarah Reid Campbell-Lemuel Dunn
Margaret J Dunn-Archibald Allen
George R Allen-Nancy McCoy
Edward Allen-Edith Knott
Vernon/Edith/Corinne/Tessora/Richard 
The rest of us-we know who we are!