This report describes the water-resources activities of the U.S. Geological Survey, Wyoming District hydrologic-data-collection programs and water-resources-appraisal projects. Much of the work is done in cooperation with other agencies. During Fiscal Years 1988 and 1989, cooperators included 10 State agencies, 5 counties, 3 cities, 2 towns, 1 irrigation district, 2 Indian Tribes, and 8 Federal agencies. This report serves both as a biennial progress report to the cooperating agencies and the general public, and as one means of coordination of water-resources activities with other agencies. Lists and location maps are included for 180 streamflow stations, 6 reservoir stations, 120 surface-water-quality stations, 15 sediment stations, 88 groundwater level observation wells, and 73 groundwater quality sites that were in operation during Fiscal