Steve, I have always interpreted the maps to show the county line passing diagonally through the intersection of Glen Falls Road and the railroad, then crossing Glen Falls Road agian as the latter curves back to the northeast. North of the railroad and west of Glen Falls Road is in Carroll County; east of the road is observer's choice, though the closer to the railroad the more likely to be Baltimore County. Incidentally, I saw my life Brewster's Warbler at Glen Falls on May 28, 1978. It was a singing male along the railroad about a quarter mile east of Glen Falls Road. It was the white-wing barred type. Did you get a look at the wing bars on yours? Bob Ringler Eldersburg