Water-quality data have been collected intermittently at several sites in the Bear River basin since 1947. Because the Bear River flows through three States - Utah, Wyoming, and Idaho - water-quality programs have been confined for the most part within State boundaries. In 1967, the U.S. Geological Survey, as a part of its cooperative program with the Utah Department of Natural Resources, Division of Water Rights, designed a reconnaissance to obtain needed water-quality information for the entire basin. This report presents the results of the data-collection phase of the reconnaissance. Also included in this report are data collected intermittently or periodically prior to the reconnaissance by the U.S. Geological Survey, the U.S. Bureau of Reclamation, and the Federal Water Pollution Control Administration. An interpretive report is being prepared and will be published by the U.S. Geological Survey as a Hydrologic Atlas.