In 2016-2019 water samples were collected at Lake of the Woods as part of a research program to determine sources and fate of nutrients in nearshore areas. These included samples of lake water, groundwater, streams, and septic wastewater. The samples were analyzed for nutrients (total and dissolved P, nitrogen species, artificial sweeteners and other trace contaminants, major ions and various dissolved metals and other elements. Some of these data have been used/published in journal articles (Robertson et al., 2019, 2021; Van Stempvoort et al., 2019, 2020, 2021; Danielescu et al., 2021).