This report presents a compilation of geologic and hydrologic information for the Bullhead City-Black Mountains area of we stem Arizona. The purpose of the project is to determine the significance of mining, geology, and geohydrology in the chemistry of Bullhead City area groundwater. Mining in the Black Mountains has taken place since the 1800s, and the region provides a good opportunity to investigate any links between mining and water quality. The study encompasses the area from the crest of the Black Mountains on the east, the Colorado River on the west, latitude 350 on the south and the top of township 2IN at the north (Figure 1). Information was compiled from published and unpublished sources including U.S. Bureau of Land Management, U.S. Geological Survey, U.S. Bureau of Mines, U.S. Natural Resources Conservation Service (Department of Agriculture), Arizona Geological Survey, Arizona State Land Department, Arizona Department of Water Resources, and Arizona Department of Environmental Quality.