Water resources data for Montana for the 2002 water year consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels in wells. This report contains discharge records for 244 streamflow-gaging stations; stage or content records for 9 lakes and large reservoirs and content for 31 smaller reservoirs; water-quality records for 142 streamflow stations (42 ungaged), 9 ground-water wells, and 3 lakes; precipitation records for 2 atmospheric-deposition stations; and water-level records for 53 observation wells. Additional water year 2002 data collected at crest-stage gage and miscellaneous-measurement sites were collected but are not published in this report. These data are stored within the District office files in Helena and available on request. These data represent part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Montana.