The Tanacross quadrangle, consisting of 17,400 km 2 (6,700 mi 2) in east-central Alaska, was investigated by an interdisciplinary research team for the purpose of assessing the mineral resource potential of the quadrangle. This report provides the background information for a folio of maps on the geology, geophysics, reconnaissance geochemistry, Landsat imagery, and mineral resource evaluation of the quadrangle. Revisions to the previously published geologic map of the Tanacross quadrangle, 18 new potassium-argon ages, and a comprehensive bibliography are also included.