Using a variety of remotely-sensed data, a worldwide survey of river-generated megafans is presented. Thus far, 272 partial cones reaching minimum lengths and widths of 80 km and 40 km, respectively, have been identified. They all indicate large areas of fluvially-laid sediment distant from present or past shorelines. This more than doubles prior counts of fans of these dimensions, partly as a result of using a different set of criteria. All are visible either as pristine or degraded features, and it is likely that more will be found as older, more eroded individual occurrences are identified. The greatest numbers are found in Asia (n = 87), from Iraq to the clusters of megafans on the south flank of the Himalaya, and also in central Asia. Africa displays a similar number (n = 87), almost all related to relatively low-relief topographic swells. In South America (n = 60), most megafans are found clustered along the east flanks of the Andes Mountains and include the longest known example (704 km). Few occur in Europe (n = 9) or North America (n = 1), in both cases as a result of incisional fluvial regimes operating almost continent wide. Australia hosts 28 megafans. River-generated fans with smaller dimensions are numerous on all continents, however.