Why Great Lakes Ships Couldn't Reach the Atlantic: Niagara Falls Blocked the Way

Niagara Falls—a 50-m (167-ft) drop on the Niagara River between Lake Erie and Lake Ontario—created an impassable barrier between the Great Lakes and the Atlantic Ocean.

Two Engineering Solutions

1. Welland Canal (Canada)

• First opened 1829; current (4th) version 1932.
• 43.4 km (27 mi), 8 locks, lifts/lowers 99.5 m (326 ft).
• Bypasses Niagara Falls entirely; connects Lake Ontario to Lake Erie.
• Capacity: ~3,000 transits/year; max vessel: 225.5 m × 23.8 m (Seawaymax).

2. St. Lawrence Seaway (US/Canada)

• Opened 1959; joint management.
• 3,700 km (2,340 mi) from Duluth, MN to Atlantic.
• 15 locks (7 on St. Lawrence R., 8 on Welland Canal).
• Same Seawaymax dimensions.
• Seasonal: ~March–December (ice closes winter).

Before Canals

Portage around Niagara (Lewiston to Queenston) was the only option—slow, costly, limited capacity. The Erie Canal (1825) connected Hudson River to Lake Erie, but still required Lake Ontario transit.

Modern Reality

Great Lakes–Atlantic shipping is routine but constrained by lock size, season, and tolls. "Lakers" (lake-only freighters) are too big for Seaway locks; "Salties" (ocean-going) fit. Cargo transfers at Montreal or transload terminals.