Water-resources data for Colorado for the 2004 water year (WY) in this report consist of records of stage and discharge of streams; and stage and contents of one reservoir. This report contains discharge records for 312 gaging stations, stage and contents of 1 lake and reservoir, discharge measurements for 1 partial-record low-flow station and 1 miscellaneous site, and peak-flow information for 22 crest-stage partial-record stations. Three pertinent stations operated by bordering states, and 34 stations operated by the Colorado Division of Water Resources are included in this report. All records (except as just noted) were collected and computed by the Water Resources Discipline of the U.S. Geological Survey under the direction of J.E. Kircher, Director, USGS Colorado Water Science Center. These data represent that part of the National Water Information System collected by the U.S. Geological Survey and cooperating State and Federal agencies.