There is an archival map of Tennessee's 3rd Surveyor's District at the Tennessee State Library and Archives in Nashville, dated about late 1807. This map, No. 399 is very large. The towns of Cookeville, McMinnville, Sparta and Spencer did not exist in 1807. For most of the 3rd District's twenty year lifespan, 1807-1827, the 3rd District was considered to be in West Tennessee. However, earlier, North Carolina considered that area to be in her Middle District and is so reflected in her land grants there. The western bounds of the North Carolina Middle District were the east bounds of the North Carolina Military District, also known as the Military Reservation. Many North Carolina plats of grants are shown on the map as are also a few 1807 Tennessee plats. It is possible that the map was never finished for great many older North Carolina grants in the area are not drawn on the map. Many, but not all, of the grants have been identified.
There are 23 identified large grants shown on the 3rd Surveyor’s District map plus 69 small grants in the Sparta area. There is a large grant near the junction of Calfkiller Creek and Cainey Fork River that is identified as belonging to Thomas McCORRY. This is the only place I have seen McCorry so I assume it could be a misspelling or misreading of old handwriting. I haven’t seen the actual map but it is very possible that this could actually be Thomas McGARRAH.
If Thomas McGarrah received a land grant it would explain the McGarrah families making their move to Tennessee.