This tabular data set represents PRISM 30-year average Potential Evapotranspiration, 1971-2000 compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments 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 for the PRISM 30-year average Potential Evapotranspiration, 1971-2000 was produced by Hamon, 1961; DiLuzio and others, 2008. Units are millimeters per year. It should be noted this data set is discontinued and available only by contacting the PRISM Group at Oregon State University directly. 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).