I have found DNA Matches who trace their genealogy back to Thomas McGrew who (so far) first appears on record in the 1790 South Carolina Federal Census.
At least two of my male cousins – descendants of Thomas McGraw, son of Martin McGRAW Sr (PA>WV). – submitted Y-DNA tests to familytreedna.com. The McGrew Project Administrator made it known when Fred McGrew submitted his test in 2013 that his Y-DNA matched that of the descendants of Thomas McGrew (b. circa 1732 PA>SC>KY) 36 out of 37 markers. The assumption is that Thomas McGrew was an uncle or a cousin of Martin McGraw, Sr. The article was written by John G. McGrew and is available here:
https://www.genealogy.com/forum/surnames/topics/mcgraw/1642/
Further, I was contacted in March 2020 by a DNA Match in Ancestry asking how we are related. At the time, I didn’t know. Now I do. Ellen McGrew is a direct descendant of John Lewis McGrew who was a descendant of Thomas McGrew. We share enough centiMorgans to make us 5th-8th cousins. While most people ignore 5th-8th cousin DNA Matches, I put great stock in them as this is the second occasion in which I’ve been able to break through a brick wall and/or locate the next generation ancestor. In this case, I’m on the cusp of finding the next generation ancestor of our McGraw / McGrew line.
Now for a little history about Thomas McGrew. He applied for a Revolutionary War Pension in Calloway County, Kentucky in 1832. Although he was in his 90’s, his age apparently didn’t seem to affect his memory too badly as he was able to recall the names of his commanding officers and at least one battle in which he was engaged: The Seige of Ninety-Six. Most fascinating of all is the last paragraph of the document in which he states he was “born and raised in Pennsylvania from which state he removed to South Carolina before the Revolution.” You can read the transcribed document here on RevWarApps.org:
http://www.revwarapps.org/s13895.pdf
On to busting through this brick wall.