Title in lower margin: Loudoun Co., Va., N3850.5-W7719/29.5X39.5 : 1977. "Compiled in 1977 from USGS 1:24,000-scale topographic maps dated 1968-1972." "Planimetry revised from photographs taken 1973 and other sources." UTM grid. Includes notes. Available also through the Library of Congress Web site as a raster image.
Geological Survey (U.S.)
1977
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