In 2024, the U.S. Geological Survey (USGS), in collaboration with the Cook County Bureau of Technology (BOT), carried out comprehensive hydrographic and water-quality surveys, and activity and disturbance assessments of 44 total water bodies encompassing lakes and rivers within Cook County, Illinois. These surveys and assessments describe the bathymetry, water-quality conditions, and on-site field crew observations and impressions for each water body and its surrounding catchment area. Data collected may assist the BOT with resource management decisions and practices and contribute to an inventory that can be shared with other local governmental agencies. Included in this data release are bathymetric, water quality, and observational findings gathered in 2024 for the following water bodies listed in alphabetical order: Barrington Road Pond, Butterfield Creek Lake, Cermak Quarry, Chicago Botanic Garden lakes (East Lake, Great Basin, Japanese Garden Lake, North Lake, Prairie Lake, South Lake, and West Lake (includes Spider Pool)), Cranberry Slough, Des Plaines River, Dr. Mary Woodland Reservoir, Eggers Grove Marsh, Glenbrook Park Lake, Indian Ridge Marsh Ponds (1, 4, 5, and 8), Lake Sedgewick, MacIntyre Pond, Margreth Riemer Reservoir East, Margreth Riemer Reservoir West, O'Malley Ponds (Central, North, and South), Penny Road Pond, Peregrine Lake, Phoenix Lake, Plum Grove Reservoir, Poplar Creek, Potawatomi Pond, Rolling Knolls Pond, Schiller Pond, Schultz Park Lake, Skokie Lagoon 3 Channel (main lagoon surveyed in 2023), Skokie River, Spring Creek Valley North, Thatcher Glen Pond, Tom T. Hamilton Reservoir, Volkening Lake, and Whitford Pond. First posted August 23, 2024, ver. 1.0 Revised February 11, 2025, ver. 2.0