This tabular data set represents the number and density of major National Pollutant Discharge Elimination System (NPDES) sites, as defined by Environmental Protection Agency (EPA), compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) number and desnity of major sites per individual reach catchments and 2) number and density of major sites accumulated upstream through the river network. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data was acquired by James Falcone (USGS, written commun., 2010) from the EPA. Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).