Since 1979, the Geothermal Research Program of the U.S. Geological Survey (USGS) has carried out a multidisciplinary research effort in the Cascade Range. The goal of this effort is to understand the tectonics, geology, and hydrology of the Cascades as a framework for characterizing and quantifying its geothermal resources. In May 1985, 5 years after an initial USGS-sponsored Cascades conference [Bacon, 1980], the Geothermal Research Program again sponsored a workshop on geothermal resources of the Cascade Range. Motivation for the workshop came primarily from the conviction within the Geothermal Research Program that the Cascade effort had advanced sufficiently that a forum with an explicitly geothermal focus was needed to promote the synthesis of ideas from diverse research projects. In addition, it was thought that research drilling plans in the Cascades that were being formulated by various other agencies also could benefit from the examination and evaluation that a workshop would foster. Accordingly, the workshop was designed to develop a common understanding of the status of various investigations among USGS and other scientists working in the Cascades, to stimulate renewed interest in understanding the geothermal regime of this volcanic chain, and to encourage the tectonic, geologic, and hydrologic synthesis necessary for a quantitative assessment of geothermal resources of the Cascades, a major objective of the USGS Geothermal Research Program.