Reliable peak-streamflow information is critical for proper design of stream-related infrastructure, such as bridges, and StreamStats is a Web-based Geographic Information Systems (GIS) application that provides a user-friendly interface to estimate peak flows (https://streamstats.usgs.gov/ss/). StreamStats develops these peak-flow estimates using basin characteristics for the entire contributing area to a user-selected point; however, infrastructure planners often need to estimate flows for an area downstream from a known control such as a reservoir release or a weir. This dataset was compiled in cooperation with the South Carolina Department of Transportation (SCDOT) to provide a GIS layer of filtered regulation points from the U.S. Army Corps Engineers (USACE) National Inventory of Dams and upstream basin polygons for those points, for use within the South Carolina StreamStats client application. A select few characteristics were computed for each basin in the polygon dataset to enable the application to estimate flows above and below each regulation point and better assist SCDOT personnel when designing new or revising existing stream-related infrastructure.