Lake Superior: The Greatest of the Great Lakes by Surface Area
Lake Superior (Ojibwe: *Gichigami* — "great sea") is the **largest freshwater lake by surface area on Earth** — 82,100 km² (31,700 sq mi). It defines the **upper Great Lakes** and the **US-Canada border**.
Location & Boundaries
- Countries: USA (south/west) & Canada (north/east)
- US States: Minnesota (west), Wisconsin (south), Michigan (Upper Peninsula, north/east)
- Canadian Province: Ontario (north/east)
- Coordinates: 46°–49°N, 84°–92°W
Superlative Statistics
| Metric | Value | Rank |
|---|
| Surface area | 82,100 km² (31,700 sq mi) | #1 freshwater globally |
| Volume | 12,100 km³ (2,900 cu mi) | #3 globally (Baikal, Tanganyika) |
| Max depth | 406 m (1,333 ft) | Deepest Great Lake |
| Avg depth | 147 m (483 ft) | — |
| Shoreline | 4,385 km (2,726 mi) incl. islands | — |
| Water retention | 191 years | Longest of Great Lakes |
| Elevation | 183 m (600 ft) above sea level | — |
Geology & Hydrology
- Origin: Midcontinent Rift (1.1 Ga) + glacial scouring (Pleistocene)
- Bedrock: Precambrian Canadian Shield (granite, gneiss, basalt)
- Inflow: 200+ rivers (Nipigon, St. Louis, Pigeon, Tahquamenon)
- Outflow: St. Marys River → Lake Huron (regulated by Compensating Works)
- Islands: Isle Royale (US NP), Apostle Islands (WI), Slate Islands (ON)
Ecology & Economy
- Fish: Lake trout, whitefish, walleye, salmon (stocked), herring — commercial & sport
- Shipping: 80M tons/yr (iron ore, grain, coal) via Soo Locks (busiest lock system)
- Tourism: Pictured Rocks, Apostle Islands, Isle Royale NPs; kayaking, wreck diving
- Water supply: Duluth, Thunder Bay, Marquette, Sault Ste. Marie
Climate Change Sentinel
- Ice cover decline: 79% reduction (1973–2023); 2024 near-record low
- Summer temp rise: +2.7°C (1980–2020) — fastest-warming large lake
- Stratification changes: Longer stratified period → hypoxia risk
Lake Superior: **cold, vast, ancient, and increasingly fragile** — the freshwater inland sea that anchors a continent.
Wanderlust World