Water resources data for the 1999 water year for Maryland and Delaware consist of records of water levels and water quality of ground-water wells. This report (Volume 2. Ground-Water Data) contains water levels at 395 observation wells, discharge records for 6 springs and water quality at 1 spring, 186 wells, and 27 streambed piezometers. Locations of ground-water level wells are shown on figures 5 and 6. Locations of ground-water-quality sites are shown on figure 7. The data in this report represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland and Delaware.