Streamflow and precipitation data collected at and near Yucca Mountain, Nevada, during water years 1986-90 are presented in this report. The data were collected and compiled as part of the studies by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, to characterize surface-water hydrology in the Yucca Mountain area. Streamflow data include daily-mean discharges and peak discharges at 5 continuous-record gaging stations, and peak discharges at 10 crest-stage, partial-record stations and 2 miscellaneous sites. Precipitation data include cumulative totals at 20 stations maintained by the U.S. Geological Survey and daily totals at 15 stations maintained by the Weather Service Nuclear Support Office, National Oceanic and Atmospheric Administration.