We report chemical analyses of stream-water, stream-sediment, soil, soil-water, bedrock, and vegetation samples collected from the headwaters of the Delta River (Tangle Lakes District, Mount Hayes 1:250,000-scale quadrangle) in east-central Alaska for the period June 20-25, 2006. Additionally, we present mineralogic analyses of stream sediment, concentrated by panning. The study area includes the southwestward extent of the Bureau of Land Management (BLM) Delta River Mining District (Bittenbender and others, 2007), including parts of the Delta River Archeological District, and encompasses an area of about 500 km2(approximately bordered by the Denali Highway to the south, near Round Tangle Lake, northward to the foothills of the Alaska Range (fig. 1). The primary focus of this study was the chemical characterization of native materials, especially surface-water and sediment samples, of first-order streams from the headwaters of the Delta River. The impetus for this work was the need, expressed by the Alaska Department of Natural Resources (ADNR), for an inventory of geochemical and hydrogeochemical baseline information about the Delta River Mining District. This information is needed because of a major upturn in exploration, drilling, and general mineral-resources assessments in the region since the late 1990s. Currently, the study area, called the 'MAN Project' area is being explored by Pure Nickel, Inc. (http://www.purenickel.com/s/MAN_Alaska.asp), and includes both Cu-Au-Ag and Ni-Cu-PGE (Pt-Pd-Au-Ag) mining claims. Geochemical data on surface-water, stream-sediment, soil, soil-water, grayleaf willow (Salix glauca L.), and limited bedrock samples are provided along with the analytical methodologies used and panned-concentrate mineralogy. We are releasing the data at this time with only minimal interpretation.