This product contains 1,297 watershed boundaries for water quality study sites of the U.S. Geological Survey (USGS) National Water Quality Program (NWQP) Surface Water Trends project. These include sites where water quality information was collected by both USGS and non-USGS agencies. The data consist of 1,285 boundaries in the conterminous United States, and 12 in Puerto Rico. Twenty-seven percent of boundaries were assembled from other efforts within the USGS which are using the same sites, and 73 percent of boundaries were created new for this project. The data are posted as a single shapefile with separate polygons for each boundary.