Countries Between Which the St. Lawrence Seaway Lies

The **St. Lawrence Seaway** does **not pass *between* two countries** as a border. Instead, it is a **binational deep-draft navigation system** connecting the **Great Lakes to the Atlantic Ocean**—**entirely within Canada and the United States**.

Geography

• Western Terminus: **Lake Erie (Port Colborne, ON / Erie, PA)** — **Welland Canal** bypasses Niagara Falls.
• Core: **Lake Ontario → St. Lawrence River → Gulf of St. Lawrence**.
• Key Locks (Canada): **St. Lambert, Côte Ste. Catherine, Beauharnois, Snell, Eisenhower (US/CA border), Iroquois**.
• Key Locks (US): **Eisenhower (shared), Snell (shared)** — **actually all locks are binational operations**.

Jurisdiction

• Canada: **St. Lawrence Seaway Management Corporation (SLSMC)** — manages **Canadian sections (13 locks, channels)**.
• United States: **Great Lakes St. Lawrence Seaway Development Corporation (GLS)** — manages **US sections (2 locks: Eisenhower, Snell — jointly operated)**.
• Joint: **Binational regulations, tolls, traffic control, environmental standards.**

What It Connects

**Great Lakes Ports (Duluth, Chicago, Detroit, Cleveland, Toledo, Toronto, Hamilton, Montreal)** ↔ **Atlantic Ocean (global markets)**. **~2,300 mi (3,700 km) inland navigation**.

Not a Border

The **St. Lawrence River** *does* form part of the **Canada–US border** (from Lake Ontario to ~45°N). But the **Seaway**—the **engineered channel, locks, and canals**—is a **shared infrastructure corridor**, not a boundary. **Both nations operate it as a single system**.