My oldest proven ancestor is Henry Rutherford. I descend through Earnest Rutherford, his son. That line settled in Loyston, TN--a town that no longer exists. Loyston was inundated by Norris Lake (a TVA project). Before they officially flooded the town, TVA moved the graves to New Loyston Cemetery. But, much of the family prior to Henry were probably in unmarked graves. I've always heard that some unmarked graves were left behind.
Samuel Sharp, also an ancestor of mine, I believe was with Absolum Rutherford when they came to East TN. Samuel Sharp is buried in Corryton (Knox County, TN) down Corryton-Luttrell Rd in what is called, the "Old Keys Cemetery."
There is a book called "Footprints" put out by Union County of all marked graves in the county. You can call the Union County Historical Society in Maynardville, TN. They could help you look those people up to see if they are buried in Union County. My Rutherfords were very near the Union/Anderson County line and some lived in Union County. Union County wasn't formed until the 1850's, so some of the county's graveyards were once in parts of several counties including Knox and Anderson.