Geologic Map of Loudoun County, Virginia

Introduction The geology of Loudoun County, Va., was mapped from 1988 through 1991 under a cooperative agreement between the U.S. Geological Survey (USGS) and the Loudoun County Office of Mapping and Geographic Information. This geologic map was compiled in 1993 from a series of detailed published and unpublished field investigations at scales of 1:12,000 and 1:24,000. Some of these same data were compiled as a digital geologic map at 1:100,000 scale (Burton and others, 1992a) and were the basis for a cost-benefit analysis of the societal value of geologic maps (Bernknopf and others, 1993).