This web site provides access to HYDRO1k, a geographic database developed to provide comprehensive and consistent global coverage of topographically derived data sets, including streams, drainage basins and ancillary layers derived from the U. S. Geological Survey’s 30 arc-second digital elevation model of the world (GTOPO30). HYDRO1k provides a suite of geo-referenced data sets, both raster and vector, which will be of value for users who need to organize, evaluate, or process hydrologic information on a continental or regional scale. Data sets are available for displaying continental maps of Asia and Africa with layers for attributes such as elevation, compound topographic index, slope, aspect, flow direction, flow accumulation, drainage basins, and streams. Links are given to sample applications of the database.