The following data are presented for test well USW H-6: drilling operations, lithology, availability of borehole geophysical logs , water levels, future availability of core analyses, water chemistry, pumping tests, and packer-injection tests. The well is one of a series of test wells drilled in and near Yucca Mountain adjacent to the Nevada Test Site, Nye County, Nevada, in cooperation with the U.S. Department of Energy. These investigations are part of the Nevada Nuclear Waste Storage Investigations to identify suitable sites for underground storage of high-level radioactive wastes. Test well USW H-6 was drilled to a total depth of 1,220 m. Rocks penetrated are predominantly ash-flow tuffs. Lava was encountered from 877 to 1 ,126 m. The composite static water level is approximately 526 m below land surface. The well was pumped during two periods. Maximum drawdown was about 18 m after pumping for 4,822 min at 28 L/sec, and 12 m after pumping for 2,226 min at 27 L/sec. A borehole flow survey showed that 91% of the water withdrawn from the well came from the depth intervals from 616 to 631 m, and from 777 to 788 m. (Author 's abstract)