The National Uranium Resource Evaluation (NURE) program was initiated by the Atomic Energy Commission (now the Department of Energy; DOE) in 1973 with a primary goal of identifying uranium resources in the United States. The Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program was one of nine components of NURE. Planned systematic sampling of stream sediments, soils, groundwater, and surface water over the entire United States began in 1975 under the responsibility of four DOE national laboratories: Lawrence Livermore Laboratory (LLL), Los Alamos Scientific Laboratory (LASL), Oak Ridge Gaseous Diffusion Plant (ORGDP), and Savannah River Laboratory (SRL). Each DOE laboratory developed its own sample collection, analytical, and data management methodologies and hired contractors to collect the samples. The NURE HSSR sampling program ended prematurely in 1980. The samples were analyzed and the resultant geochemical data were released on 9-track tapes and in a series of publications. By 1984, the NURE program was finished as Congressional funding disappeared. Out of a total of 625 2-degree quadrangles that cover the entire lower 48 States and Alaska, only 307 quadrangles were completely sampled and another 86 quadrangles were partially sampled. The HSSR data consisted of 894 separate data files stored on magnetic tape in 47 different file formats. The University of Oklahoma’s Information Systems Programs of the Energy Resources Institute (ISP) was contracted by the Department of Energy to enhance the accessibility and usefulness of the NURE HSSR data. ISP created a single standard-format master file to replace 894 original files. ISP converted only 817 of the 894 original files before their funding ended. Unfortunately, this conversion process was never completed and introduced several systematic errors into the database. In 1985, the NURE HSSR sample archive, original field maps, field notes, and data tapes became the responsibility of the U.S. Geological Survey (USGS). A copy of the ISP-formatted NURE HSSR database was released as two CD-ROM publications (Hoffman and Buttleman, 1994; 1996). A new effort to recompile the NURE HSSR was begun by the USGS in 1995. All of the original 894 files have been examined, reformatted, and added to this USGS enhanced version of the NURE HSSR data. The data are contained in 2 major database files: one for water samples and one for sediment samples (which also includes soil and some rock samples.)