St. Lawrence Seaway Opens Summary

  • Last updated on November 10, 2022

The St. Lawrence Seaway made it possible for ocean traffic to travel 3,777 kilometers into the heart of the North American continent, significantly expanding trade and commerce.

Summary of Event

The dedication of the St. Lawrence Seaway on June 26, 1959, by President Dwight D. Eisenhower of the United States and Queen Elizabeth II of England and Canada climaxed the greatest joint international project in history. Never before had two countries worked in conjunction to achieve such an economic goal. The St. Lawrence Seaway opened a water route 3,777 kilometers into the heart of North America. This waterway would serve the economic needs of both nations and open their inland ports to the world. The dedication was the culmination of five years of construction and more than two centuries of speculation. The history associated with the St. Lawrence Seaway is as complex as the construction itself. Natural and human-made barriers contributed to the delay. National and international problems threatened what was to become the greatest international friendship venture ever undertaken by two bordering nations. St. Lawrence Seaway[Saint Lawrence Seaway] Canals and waterways, artificial [kw]St. Lawrence Seaway Opens (June 26, 1959)[Saint Lawrence] [kw]Seaway Opens, St. Lawrence (June 26, 1959) St. Lawrence Seaway[Saint Lawrence Seaway] Canals and waterways, artificial [g]North America;June 26, 1959: St. Lawrence Seaway Opens[06130] [g]United States;June 26, 1959: St. Lawrence Seaway Opens[06130] [g]Canada;June 26, 1959: St. Lawrence Seaway Opens[06130] [c]Transportation;June 26, 1959: St. Lawrence Seaway Opens[06130] [c]Engineering;June 26, 1959: St. Lawrence Seaway Opens[06130] [c]Travel and recreation;June 26, 1959: St. Lawrence Seaway Opens[06130] [c]Trade and commerce;June 26, 1959: St. Lawrence Seaway Opens[06130] Chevrier, Lionel Castle, Lewis Gould Saunders, Robert Moses, Robert Casson, Dollier de Merritt, William Hamilton

The St. Lawrence River flows northeast to the Atlantic Ocean. The problem was 1,609 kilometers up the river from its mouth, at Montreal, Canada. From there, the water rises to a height of 75 meters above sea level at Lake Ontario, and eventually at the other end of the Great Lakes rises to a height of 183 meters above sea level. A water route was needed to bypass the 304-kilometer rapids and unnavigable sections so ocean vessels could get to the inland ports of the Great Lakes.

Jacques Cartier discovered the 161-kilometer-wide gulf on St. Lawrence’s Day in 1535. He sailed up the river, which he named after St. Lawrence, looking for a northwest passage to China. Samuel de Champlain, known as the father of Canada, came many years later and served the people along the river.

Dollier de Casson, Superior of the Sulpecian seminary, looked out over the Lachine Rapids and dreamed of a plan that would bring missionaries, settlers, trappers, and traders up the rapids and into the lakes beyond. He planned to build a canal to bypass the rapids. Unfortunately, by his death in 1701, only a 1,829-meter dike had been excavated.

William Hamilton Merritt, a businessman in the Niagara Peninsula, was a forerunner in canal building. He proposed the Welland Canal to bypass the rapids and falls on the Niagara River. The 1.2-meter-deep, 171-kilometer canal would connect Lake Ontario with Lake Erie. This canal would have an ascent of 109 meters accomplished by forty wooden locks.

By the beginning of the nineteenth century, the St. Lawrence River had established itself as a freight route to the east. A variety of flat-bottomed river boats carried wheat, flour, lumber, and other goods between Montreal and Quebec. The Lachine, Beauharnois, and Cornwall canals and a second Welland Canal were built by the mid-1800’s. At that time, a 2.7-meter-deep channel existed from the Atlantic Ocean to Detroit, Michigan, and Windsor, Ontario.

This last restraining dam on the river was blown up, thereby flilling the St. Lawrence Seaway.

(National Archives)

Severe northern winters closed the canals for five months every year. Shippers wanted to maximize their seven-month season. By 1904, a 4.2-meter channel ran from Lake Erie to Montreal. Connecting channels were constructed between Lake Huron and Lake Erie and through the Canadian Sault Canal to connect all of the Great Lakes. It was now possible for larger ships with greater amounts of cargo to pass through the canals.

The earlier part of the twentieth century saw ships getting larger and carrying greater amounts of cargo over the world’s oceans. It was now time for serious consideration of a joint project to develop a seaway from Montreal to Lake Ontario. World Wars I and II delayed discussion of the project, and the United States Congress failed to pass legislation pertaining to the seaway.

Canada took the initiative after World War II in both improving the seaway and developing hydroelectric power projects. At one point, it even considered doing both projects alone. Lionel Chevrier, Canadian Minister of Transport in 1947, took a leading role in developing plans for both projects, as well as negotiating with representatives of the United States to find out their interests toward the projects. The power project received first attention.

Ontario Hydro-Electric Power Ontario Hydro-Electric Power[Ontario Hydroelectric Power] and the Power Authority of the State of New York Power Authority of the State of New York New York State Power Authority agreed to develop power on the St. Lawrence in 1950. These agencies were headed by Robert Saunders and Robert Moses, respectively. A powerhouse 1,006 meters long was to be built jointly west of Cornwall. The river would be backed up 45 kilometers, creating a 161-square-kilometer lake. Many farms and small villages as well as factories, roads, and railroads tracks would be under water. More than six thousand people would have to be relocated.

Two dams were also in their plans. The first, at Long Sault, would be 762 meters long and would control the water flow to the great powerhouse. The second, at Iroquois, would be 747 meters long and control the outflow from Lake Ontario. The cost to the two power agencies would total $650 million. This was the first great step to the development of the seaway.

The problem of moving towns, bridges, people, industry, and traveling routes fell to the power agencies. Even the river would be diverted in places during construction. New towns sprang up. The integrity of the land was preserved as many of the old homes blended with the new ones. The great advantage, however, was that now the seaway could become a reality. Canada took the initiative. It was determined to move ahead whether or not the United States chose to participate. Chevrier was named president of the St. Lawrence Seaway Authority.

President Harry S. Truman wanted the United States to participate, but Congress failed for a fourth time to authorize American participation. Only after President Eisenhower was elected did the United States move forward on the project. He signed an executive order giving the Power Authority of the State of New York the authority to represent the United States in the power venture.

In 1954, Congress passed the Wiley-Dondero Act, Wiley-Dondero Act (1954)[Wiley Dondero Act] allowing the United States to participate in the St. Lawrence Seaway project. It was a great victory for both countries. Governor Thomas E. Dewey of New York, Premier Leslie M. Frost of Ontario, and Prime Minister Louis St. Laurent of Canada met on August 10, 1954, to break ground. Lewis Gould Castle was chosen administrator of the St. Lawrence Seaway Development Authority, the U.S. agency set up to do work on the American side of the river. Work began immediately. The first contracts were out by October; both countries wanted to get started before winter set in.

Six main structures were constructed for the generation of power: a powerhouse across the north channel of the St. Lawrence connecting the Canadian mainland and Barnhart Island, a powerhouse spilling dam across the south channel connecting the United States with Barnhart Island, a control dam at Iroquois to regulate the overflow of Lake Ontario, dikes as necessary to regulate the pool level at and above Barnhart Island, a canal closure structure in the Canadian dike next to the powerhouse to maintain a 4.2-meter depth for navigation during construction, and a controlled intake at the mouth of the Messena Canal. Seven locks were built between Montreal and Lake Ontario. Three were in the International Rapids section. Eight locks remained on the Welland Canal between Lakes Erie and Ontario.

Work went extremely slowly at first. Millions of tons of clay had to be moved. The largest earth-moving machines in the world were brought in to do the work. Potsdam sandstone, one of the hardest rocks in the world, had to be drilled and blasted. Once this rock was removed, it was used in retaining dikes along the channel. Another problem encountered was the severe weather. Temperatures reached 35 degrees below zero. Concrete would freeze before it was set, so preheated sand, gravel, and water were used in the concrete mixture. In 1957, floodwaters from hurricane Audrey threatened work.

In less than five years, one of the greatest projects undertaken by two nations was complete. Locks up to 9 meters deep, almost 274 meters long, and 24 meters wide now could handle ocean vessels of 10,000 tons and lake transports up to 25,000 tons if their draft was not more than 7.8 meters. The original twenty-two small locks had been replaced by seven large ones, making the ascent from Montreal to Lake Ontario an even water stairway. The total cost was $450 million. The final cost of the power and navigation projects was more than $1.2 billion.

It took ten years to complete the Suez Canal, twenty-four years to construct the Panama Canal, and more than thirty years to build the first St. Lawrence Canal system. Each phase of construction on the seaway was completed on time or ahead of time. The joint effort by all authorities involved proved that private, state, national, and provincial groups could work together with the cooperation of two nations.


The completion of the St. Lawrence Seaway opened a water route that stretches 3,777 kilometers into North America. The largest ships in the world can carry cargoes into and out of North America by the cheapest method—water.

More than $1 billion was spent on developing the power and seaway projects. More than twenty-two thousand people were employed on the projects. Indirectly, tens of thousands more were touched: those who made the machines used on the projects and those who transported them to the work sites. In addition to salaries paid to workers, the areas surrounding the seaway reaped its benefits.

The State of New York and the Province of Ontario receive power from the power plants on the St. Lawrence River. The potential “white power” to the area is between 25 and 30 million horsepower produced by water on its way to the sea. Fifty-seven million tons of coal would be needed annually to produce the same horsepower.

The area that is reached by shipping corresponds closely to the size of western Europe. The opening of the seaway included a sharp drop in shipping costs and a downward press on shipping rates. New business was created for Quebec ports on the river as well as for both countries on the Great Lakes.

Grains, raw materials, and automobiles are shipped to world ports through the seaway. Until the mid-twentieth century, the great iron and steel producers were located on the Great Lakes, and these products also went to foreign and domestic ports via the seaway. The deep waterway permitted the movement of bulk goods in far more economic quantities.

United States and Canadian ports developed the capabilities for handling ocean shipping. The United States had a concentration of heavy industry in the Great Lakes area. Now, 80 percent of the world’s ships could reach their ports. Chicago, Detroit, and Duluth joined Toronto and Hamilton as world ports. Milwaukee undertook a $5 million harbor improvement. Toledo considered a $20 million terminal. Buffalo spent $6 million on port improvements. Overseas traffic passing through the Welland Canal increased tenfold between the years 1946 and 1959.

The major development of the St. Lawrence Seaway is that it shows the world that two independent countries can build and manage a joint project of major proportion and live in harmony with its existence. An artificial boundary separates both countries along the whole of the waterway, yet both countries reap benefits from it. Cooperation and consideration between countries are possible, and a common objective can be reached. St. Lawrence Seaway[Saint Lawrence Seaway] Canals and waterways, artificial

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Chevrier, Lionel. The St. Lawrence Seaway. Toronto, Ont.: Macmillan, 1959. Chevrier relates the obstacles and problems associated with the development of such a large international program. Conveys the history of the idea of a seaway for more than one hundred years and goes into detail about the behind-the-scenes drama to get the seaway construction under way. Illustrated. For a wide audience.
  • citation-type="booksimple"

    xlink:type="simple">Hills, Theo L. The St. Lawrence Seaway. New York: Praeger, 1959. Hills, an associate professor of geography at McGill University in Montreal, writes an excellent book that is illustrated throughout. He discusses all aspects of the St. Lawrence Seaway, including history, negotiations, politics, construction, and economic advantages to all areas touched by the project. A large section covers power projects, and the final chapter discusses the future of the seaway, including a list of foreign and domestic ship traffic.
  • citation-type="booksimple"

    xlink:type="simple">Judson, Clara Ingram. St. Lawrence Seaway. Chicago: Follett, 1959. This book is designed for the younger reader. It is heavily illustrated and covers all aspects of the history and development of the St. Lawrence Seaway. Judson puts the entire area in perspective by providing good descriptions of early development and improvement.
  • citation-type="booksimple"

    xlink:type="simple">Mabee, Carleton. The Seaway Story. New York: Macmillan, 1961. Mabee writes from a personal interest point of view. He watched the seaway being built and relates the story of the politics involved by the United States and Canada during the project. He gives adequate space to problems associated with the seaway, both natural and human-made. Illustrated.
  • citation-type="booksimple"

    xlink:type="simple">Parham, Claire Puccia. From Great Wilderness to Seaway Towns: A Comparative History of Cornwall, Ontario and Massena, New York, 1784-2001. Albany: State University of New York Press, 2004. Comprehensive history of two towns—one Canadian and one American—located on the St. Lawrence Seaway. Reveals the economic, cultural, and other effects of the seaway.
  • citation-type="booksimple"

    xlink:type="simple">Payne, Robert. The Canal Builders: The Story of Canal Builders Through the Ages. New York: Macmillan, 1959. Discusses the great canals of the world through history. Pages 248 to 261 discuss the St. Lawrence Seaway. The history of the waterway from 1535 through its opening, along with the construction and international problems, is briefly but accurately covered. The young reader can compare the seaway project with other major canal projects from around the world. Illustrated.
  • citation-type="booksimple"

    xlink:type="simple">Sussman, Jennifer. The St. Lawrence Seaway: History and Analysis of a Joint Water Highway. Montreal, Que.: C. D. Howe Research Institute, 1978. This publication, part of the Canada-U.S. Prospects series, examines the Canada-United States relationship in the context of contemporary domestic and international development and provides an analysis of the relationship. Chapters deal with economic, financial, and industrial matters related to the seaway. Contains graphs and charts. Illustrated.
  • citation-type="booksimple"

    xlink:type="simple">Willoughby, William R. The St. Lawrence Waterway: A Study in Politics and Diplomacy. Madison: University of Wisconsin Press, 1961. This scholarly work discusses all aspects of the waterway project. Willoughby provides a thorough history of the idea to open a seaway and then tackles the political and natural obstacles that prevented it from happening for many years. He concentrates on the objective of navigation and the plans and proposals for navigation. Illustrated with a bibliography.

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Categories: History