A map showing ground-water levels in crystalline and metasedimentary rocks in Sadsbury, West Caln, and West Sadsbury Townships, Chester County, Pennsylvania, was constructed from water levels measured in wells from April 1993 through August 1994. Pre-1993 measurements were incorporated on the map to provide control in areas where more recent data were not available. Because little ground-water development has occurred in the areas where pre-1993 water levels were used, levels are assumed to be the same in 1993 and 1994 as they were when the measurement was made.