This data release provides phytoplankton identification, phytoplankton enumeration, chlorophyll concentration, phaeophytin concentration, phycocyanin data, and nutrient quality assurance data from three recurring algal bloom sites in Kabetogama Lake, Voyaguers National Park, Minnesota in 2016 and 2017. The goal of this research is to better understand the drivers of algal bloom toxicity in the large lakes of Voyageurs National Park so that resource managers may better predict, manage, and mitigate the occurrence of harmful algal blooms. A total of 126 environmental samples were collected at three recreational areas where blooms frequently occur. One site, Sullivan Bay, was chosen for more intensive sampling, including the algal enumeration and identification of the samples collected as part of this data release. Samples were also analyzed for field parameters, nutrients, cyanotoxins, and cyanobacteria by molecular methods. Other analyses for the three sampling locations are available in the U.S. Geological Survey National Water Information System (NWIS) at the links listed under Related External Resources/Cross References: Sullivan Bay (USGS 482542092493701), Ellsworth Rock Garden (USGS 482947092584401) and Ek Lake Trail (USGS 482804092494701). As recommended by the World Health Organization, this research will provide further data on Kabetogama Lake, where blooms have contained the toxin microcystin at levels exceeding the high-risk category for recreational exposure.