Slider Maps – Before & After The Seaway

About the St. Lawrence Seaway

The St. Lawrence Seaway is a series of locks and canals on the St. Lawrence River which allow ocean sailing vessels from the Atlantic Ocean to safely transverse the river to Lake Ontario and the Great Lakes beyond it. Early explorers of the river would encounter several rapids west of the city of Montreal, Quebec which prevented easy travel. The largest was the Long Sault Rapids found between Massena, New York and Cornwall, Ontario.

In the early 1800s a series of canals and locks were built on the Canadian Side of the river at Cornwall which allowed the ships of the day to bypass the rapids. By the early 20th century as cargo ships became larger and larger, this canal system became outdated. The need for a better system was pushed by the ever growing agricultural and industrial complexes growing along the shores of the Great Lakes in the American Mid-West.

Talks of harnessing the Long Sault Rapids in Massena for hydro-power and better navigation had been ongoing since the 1900s. In fact a water canal in Massena was constructed in 1898 diverted waters from the head of the South Sault Rapids to the Grasse River several miles south. This brought the Pittsburgh Reduction Company (Alcoa) Aluminum Smelter to the town.

World War II pushed the need for upgrades even further and in the post WWII economy and plans were laid out by the Canadian and US Government for an expanded Seaway System. Conflicts between the two governments and the hesitation of the United States to commit to such a project almost caused the upgraded Seaway System Plan to be confined entirely to the Canadian Side of the river. It was not until the Wiley-Dondero Seaway Act of 1952 passed by the US Congress did the United States commit to a joint project to upgrade the system.

The St. Lawrence Seaway and Power Project involved the construction of two US Locks and two Dams in the Town of Massena combined with flooding the shores of the St. Lawrence River to create a man made lake. Ten towns along the Canadian Shores were either demolished or relocated, while the impact on the southern shores of the US was less it did involve the relocation and destruction of many early settlements in the Massena Center and Louisville Landing area.

Construction began in 1954. The influx of laborers on both sides of the river caused a major economical boom to the Town of Massena and City of Cornwall. The project was dubbed the 8th Wonder of the World and was the largest man made engineering project of its time. On July 1st 1958 the coffer dams in Massena were dynamited and within four days the new Lake St. Lawrence was formed. The Seaway System officially opened in 1959 by Queen Elizabeth the II of Canada and Dwight D. Eisenhower of the United States.

Our Slider Maps

The following maps found below were assembled by the Massena Center Historical Society with the use of the USGS’ Historical Online Archive known as TopoView. This online system allows users to view and compare various topographic map. For the Massena / St. Lawrence Region we have utilized maps from the 1940s and 1960s. Please enjoy.

Massena Center Area

Barnhart Island

Croil & Long Sault

Wilson Hill

Coles Creek



East Ogdensburg