Field reconnaissance, geologic mapping, and photogeologic interpretations aided collectively in the identification of 30 potential high-yield well sites in the crystalline rocks of Delaware's western Piedmont. Fracture traces discernable on panchromatic and color infrared photography were identified in the study area. Well locations were selected on individual traces and on fracture trace intersections. Six test wells averaging 468.5 feet in depth were drilled at selected sites. Test analyses indicate that production wells at these sites would have a combined potential estimated at 1.0 to 1.1 million gallons per day of water. A thorough knowledge of the hydrogeologic framework is key to successful ground-water exploration and development. Subsurface fracturing is of prime importance in governing the water-yielding properties in the crystalline rocks. The surface traces of vertical or near-vertical zones of subsurface rock fracture were identified and used as an aid in high-capacity well siting.