Water resources data for the 1994 water year for Pennsylvania consist of records of discharge and water quality of streams; contents and elevations of lakes and reservoirs; and water levels and water quality of ground-water wells. This report, Volume 1, includes records from the Delaware River Basin. Specifically, Volume 1 contains (1) discharge records for 81 continuous-record streamflow-gaging stations and 27 partial-record stations; (2) elevation and contents records for 12 lakes and reservoirs; and (3) water-quality records for 25 gaging stations and 52 ungaged streamsites; and (4) water-level records for 17 observation wells. The location of these sites is shown in figures 6-9. Additional water data collected at various sites not involved in the systematic data-collection program are also presented. These data together with the data in Volumes 2 and 3, represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Pennsylvania.