Four Great Lakes Border Both the U.S. and Canada — Not Five
There are **four** — not five — Great Lakes that form the U.S.–Canada border. The fifth Great Lake lies entirely within the United States.
The Four Binational Great Lakes
| Lake | Border Length | Primary Border | Key Ports |
|---|
| Lake Superior | 1,180 mi (1,900 km) | MN/WI/MI (US) — ON (CA) | Duluth, Thunder Bay, Marquette |
| Lake Huron | 870 mi (1,400 km) | MI (US) — ON (CA) | Sarnia, Goderich, Alpena |
| Lake Erie | 530 mi (850 km) | MI/OH/PA/NY (US) — ON (CA) | Cleveland, Toledo, Erie, Port Stanley |
| Lake Ontario | 460 mi (740 km) | NY (US) — ON (CA) | Rochester, Toronto, Kingston, Hamilton |
The Fifth: Lake Michigan — 100% U.S.
- Area: 58,000 km² (3rd largest)
- States: MI, WI, IL, IN
- Connection: Straits of Mackinac (hydrologically one lake with Huron)
- Why no Canada? Southern extent (41°40′N) stays south of 45th parallel border
Governance
- Boundary Waters Treaty (1909): International Joint Commission (IJC) manages levels, quality, disputes
- Great Lakes Water Quality Agreement (1972/2012): Binational restoration targets
- Compact (2008): 8 U.S. states + 2 CA provinces — diversion bans, conservation
By the Numbers (All Five)
- Total area: 244,000 km² (94,000 sq mi)
- Volume: 22,700 km³ (5,400 cu mi) — 21% world's surface freshwater
- Coastline: 17,000 km (10,500 mi) — including islands
- Population: 34M (US) + 4M (CA) in basin
Four shared. One solo. Together: the planet's largest freshwater system.
Wanderlust World