The West Tennessee Union regiments, at least in 1862, seem to be from specific areas with captains of the companies elected by the local men they recruited. Later the new regiments were from broader areas. Co C of the 5th in East Tennessee has four out of five captains who were from Harrison in Hamilton County which would make it first guess. One source says the members of Co C were also from Bradley Co as well as Hamilton. http://72.167.204.16/fifthtennessee/officers.htm