Lake Guides
Reference pages on Ontario’s lakes as a whole, each drawn from the same provincial and federal records as the individual lake pages.
Lake Ice in OntarioIce-out and freeze-up records back to 1852, an ice thickness chart, and ice hut dates by zone.
Lake Water Levels in OntarioGauge records for 26 lakes and Georgian Bay, the bodies that set lake levels, and where each day's level is published.
Lake Water Temperature in OntarioWater temperature by month and depth near Dorset and on Lake Simcoe, how lakes layer and turn over, and where the day's reading is published.
Fishing Seasons in Ontario, Zone by ZoneThe 2026 season for six species in every fisheries management zone, and each lake's zone.
Fish Stocking in Ontario LakesFish releases into Ontario lakes from 1905 to 2025, by species, year and lake, and where the province publishes the record.
Ontario's Largest and Deepest LakesLakes ranked by surface and by charted depth, the Great Lakes' figures, and the province's count of lakes.
Lake Water Quality and Blue-Green Algae in OntarioPhosphorus and clarity at Lake Partner sites, the trophic bands, blue-green algae and invasive species.
Boat Launches on Ontario LakesBoat launches and shoreline access in the province's register by county, and the access points marked on each lake.
Pictures
- Lake Ice in Ontario: Georgian Bay and Lake Simcoe under ice, February 12, 2025. MODIS on NASA's Terra satellite, from NASA Worldview.
- Lake Water Levels in Ontario: The Bala dams at the outlet of Lake Muskoka, from the air. SCOOP2023. Imagery © King's Printer for Ontario, used under the Open Government Licence – Ontario.
- Lake Water Temperature in Ontario: Sand shallows off the beach at Mara Provincial Park, Lake Simcoe, from the air. SCOOP2023. Imagery © King's Printer for Ontario, used under the Open Government Licence – Ontario.
- Fishing Seasons in Ontario, Zone by Zone: Smallmouth bass. Painted by Duane Raver for the U.S. Fish and Wildlife Service. Public domain.
- Fish Stocking in Ontario Lakes: Brook trout. Painted by Duane Raver for the U.S. Fish and Wildlife Service. Public domain.
- Ontario's Largest and Deepest Lakes: Lake Huron, Georgian Bay, Lake Erie, Lake Ontario and Lake Simcoe, August 19, 2022. MODIS on NASA's Terra satellite, from NASA Worldview.
- Lake Water Quality and Blue-Green Algae in Ontario: A blue-green algae bloom across western Lake Erie, October 9, 2011. MODIS on NASA's Aqua satellite, from NASA Worldview.
- Boat Launches on Ontario Lakes: The boat launch at Innisfil Beach Park, Lake Simcoe, from the air. SCOOP2023. Imagery © King's Printer for Ontario, used under the Open Government Licence – Ontario.