The Mid-Atlantic District of the U.S. Geological Survey, Water Resources Division, includes the States of Delaware, Maryland, and Virginia and the District of Columbia. The water resources program of the Mid-Atlantic District is conducted from offices located at seven sites in the three states. The program consists of two elements: Collection of basic records concerning quantitative and qualitative data for streams, reservoirs, estuaries, and groundwater; and interpretative investigations based on the water facts collected in the basic data activities. The organization and activities of the Mid-Atlantic District are described. Projects that were active during 1984, 1985, or 1986 are summarized with a listing of reports of results of water resources studies in the District that were approved between January 1980 and June 1986. (USGS)