The Wind River valley, a northwest-trending valley draining southeastward into the Columbia River Gorge near Washington’s southern border (Fig. 1), is a subject of interest in geothermal exploration. There are numerous thermal and mineral springs and seeps along and adjacent to this valley, several of which are now or were previously developed into resorts, such as Bonneville and St. Martins (Carson) Hot Springs. Temperatures measured in several temperature-gradient boreholes drilled in the early 1980s revealed elevated gradients within this valley. In addition, several water wells at the southern end of the valley, near the town of Carson, contain warm water. Based on the presence of thermal and mineral springs, relatively young intrusives, and warmer water along the valley’s axis, some workers postulate that a valley-parallel structure channels high heat flow from cooling intrusives at depth within and along the length of this valley.