Here is some info I have on these folks.Please contact me if you'd like more background.
A James Adair married who was married to Rebecca Montgomery is buried in Brookville, IN, tombstone shows dates of 1747-1831.Rebecca is also in the cemetery next to him.James was the son of a Joseph Adair, and probably Sarah Lafferty.Joseph settled near Clinton, SC and was associated with the Duncan Creek Presbyterian Church.Prior to coming to SC, Joseph appears to have been an immigrant from Ireland(Ulster, no doubt) settling in Lancaster Co, PA about 1750.A marriage record for Joseph and Sarah is in the Old Swedes Church in Wilmington, DE.Joseph was a cooper (barrel maker), and deeds in SC and tax records in PA share this common description of his profession. Joseph apparently remarried in SC to a Rebecca Long.A James is mentioned in Joseph's will as a son.Deed records in SC prove that James married to Rebecca was Joseph's son.
Rebecca was the daughter of James Montgomery, and James' will in SC in 1791 mentions Rebecca and James Adair's marriage.James was a member of the 1782 SC Legislature, and was a justice of the peace for Laurens District until shortly before his death in 1791.
The children of James and Rebecca are not well documented.There is no will or other authoritative document listing all of the children. Census records in SC in 1790 and 1800 indicate the possibility of as many of 13 children, and an obituary of one of the children in IN indicates their were 13 children.One author insists their were 12, and DAR applications show a number of possibilities.Among the names mentioned in various places:Sarah, Isaac C., Margaret Jane, George R., Robert, Ruth, Jane, Rebecca, Isabel, Joseph, James Jr., John G., and Lucretia.Two sons are documented by deed records in SC.