This U.S. Geological Survey (USGS) Data Release provides phytoplankton data from Upper Klamath Lake, OR from 5/11/2020 - 9/30/2020 from ten sites and zooplankton data from Upper Klamath Lake, OR from 5/11/2020 - 10/14/2020 from eight sites. Phytoplankton data are reported to the lowest possible taxonomic level and biovolume, biomass, and density are reported. Zooplankton data are reported to the lowest possible taxonomic level, biomass and density are also reported.