Comprehensive, long-term hydrologic data sets for watershed systems are valuable for hydrologic process research; for interdisciplinary ecosystem analysis; for model development, calibration, and validation; and for assessment of change over time. The Reynolds Creek Experimental Watershed in southwestern Idaho, United States, was established in 1960 and provides a research facility and comprehensive long-term database for science. Spatial data layers for terrain, soils, geology, vegetation, and basic site mapping features and databases for fundamental hydrologic parameters of precipitation, snow, climate, soil microclimate, and stream discharge and sediment concentration are now available for water years 1962--1996 and are described in the following eight data reports. ¿ 2001 American Geophysical Union