Water resources data for the 1991 water year for New York consist of records of stage, discharge, and water quality of streams; stage; contents, and water quality of lakes and reservoirs; and ground-water levels. This volume contains records for water discharge at 110 gaging stations; stage only at 4 gaging stations; stage and contents at 4 gaging stations, and 19 other lakes and reservoirs; water quality at 36 gaging stations; and water levels at 22 observations wells. Locations of these sites are shown on figures 8A and 8B. Also included are data for 37 crest-stage partial-record stations. Additional water data were collected at various sites not in the systematic data-collection program and are published as miscellaneous measurements. These data, together with the the data in volumes 2 and 3, represent that part of the National Water Data system collected by the U.S. Geological Survey and cooperating State and Federal agencies in New York.