The following data release contains coordinates for suspected historical spawning locations of lake whitefish (Coregonus clupeaformis) and cisco (Coregonus artedi) across the Lake Ontario basin, including the Niagara River and St. Lawrence River. These data were gathered from published and unpublished sources cited in the Atlas of the Spawning and Nursery Areas of Great Lakes Fishes (Goodyear et al. 1982) and other sources as described. We define "spawning locations" as areas having eggs or spawning fish present. When available the data also contain substrate and depth information. Pseudo-absence data used for comparison purposes are also provided in this data release. Data points were summarized using ArcGIS 10.5