Water resources data for the 1974 water year for Maine including records of streamflow or reservoir storage at gaging stations, partial-record stations, and miscellaneous sites, records of water-quality data on the chemical and physical characteristics of surface- and ground-water, and records of ground-water levels in index wells are given in this report. In Part 1, records are included for 63 gaging stations, of which 62 are streamflow discharge stations, and 1 is a lake station; also are included records for 22 crest-stage partial-record stations, and 14 miscellaneous sites. In Part 2, water quality data on chemical, physical, and biological characteristics of surface and ground water were collected from designated sampling sites at predetermined intervals such as once daily, weekly, monthly, or less frequently, and at some sites data were recorded on punched paper tape at 60minute intervals. Records are given for 38 sampling stations of which 11 are continuous record stations, and 27 are miscellaneous sites. Records of chemical analyses are also given for 21 ground-water sites. In Part 3, water level data are shown for 11 ground-water wells. Locations of surface-water stations, water-quality stations, and ground-water wells are shown in figure 2. A few pertinent stations in bordering States and Provinces are also included in this report. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey under the direction of G. S. Hayes, District Chief, succeeded by C. R. Wagner. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Maine.