Static flood inundation boundary extents were created along the entire shoreline of Lake Ontario in Cayuga, Jefferson, Monroe, Niagara, Orleans, Oswego, and Wayne Counties in New York by using recently acquired (2007, 2010, 2014, and 2017) light detection and ranging (lidar) data. The flood inundation maps, accessible through the USGS Flood Inundation Mapping Program website at https://www.usgs.gov/mission-areas/water-resources/science/flood-inundation-mapping-fim-program, depict estimates of the areal extent and water depth of shoreline flooding in 8 segments corresponding to adjacent water-surface elevations (stages) at the following 8 USGS lake gages on Lake Ontario: A – Lake Ontario (Thirtymile point) at Golden Hill State Park, NY (station number 04219796) B – Lake Ontario at Hamlin Beach State Park near North Hamlin, NY (station number 04220209) C – Lake Ontario at Braddock Heights, NY (station number 04220253) D – Lake Ontario at Ninemile Point near Webster, NY (station number 0423205342) E – Lake Ontario at Sodus Point, NY (station number 0423207760) F – Lake Ontario at Breakwater Light 2 near Fair Haven. NY (station number 04232093) G – Lake Ontario (Selkirk Shores) near Daysville Corner, NY (station number 04249071) H – Lake Ontario at Pier at Sackets Harbor, NY (station number 04250772) These datasets demonstrate the estimated extent and depth of lake flooding at specific water levels of 1-foot increments from 247.0 ft to 251.0 ft (International Great Lakes Datum of 1985). In this study, wind and seiche effects were not represented; therefore, the flood inundation maps reflect five stages for Lake Ontario that are static for the entire shoreline area of the lake. This data release is a package of flood inundation data for Lake Ontario including: 1) 8 shapefiles showing 40 estimated flood extents as polygons; 2) 40 raster datasets showing the depth of the water at 5 flood stages, divided into 8 shoreline segments; 3) 8 shapefiles showing the study limit extent of each segment; and 4) 9 metadata files (this one and one for each segment). The polygon flood extent shapefiles were developed from digital elevation models (DEMs) derived from the lidar to represent the estimated areal extent for five flood stages for the segments along the approximately 300-mile shoreline of Lake Ontario from the Coast Guard Station in Youngstown, N.Y. at the mouth of the Niagara River to Cape Vincent, N.Y. The raster files depict the depth, in feet, of the water in the inundated areas along the shoreline of Lake Ontario during the five theoretical flood stages. The depth grids were created by subtracting the digital elevation model (DEM) values (in feet) from each of five raster files representing the flood extent at each constant water level (in feet). An approximately 100-meter buffer was used as the extent into the lake, except for Segment H. Due to the numerous islands and shoreline complexity, the lidar collection extent was used for Segment H. First posted June 21, 2021, ver 1.0 Revised November 2021, ver 2.0 Version 2.0: This version of the dataset has the same data as version 1.0, but some shapefile attributes were renamed to be more accurate and clearer, and the depth-grid rasters were renamed to include the associated water surface elevation within the raster file name. Detailed version history is included in Version_History_LakeOntarioFIMDataRelease.txt Version 1.0: This version is a package of flood inundation data for Lake Ontario including: 1) 8 shapefiles showing 40 estimated flood extents as polygons, 2) 40 raster datasets showing the depth of the water at 5 flood stages, divided into 8 shoreline segments, 3) 8 shapefiles showing the study limit extent of each segment, and 4) a metadata file.