From Ohio History Central
Since the first French colonists settled in modern-day Canada, humans had attempted to improve navigation on the St. Lawrence Seaway and on the Great Lakes. People living along the Great Lakes and the St. Lawrence River hoped to allow ocean-going vessels to travel the length of the river as well as to traverse several of the Great Lakes. This would allow improved trade and better profits for people living in these areas. While the French, British, and Canadians made numerous improvements to the St. Lawrence River, especially the building of small canals to bypass rapids and falls, these various groups of people only experienced minor successes in improving the river's navigation until the twentieth century.
During the 1950s, the Canadian and the United States government worked together to create the Great Lakes St. Lawrence Seaway System. Construction began in September 1954 and was completed on July 4, 1958, although the first vessel did not traverse the entire seaway until April 1959. Queen Elizabeth II and President Dwight D. Eisenhower formally opened the seaway on June 26, 1959.
The Great Lakes St. Lawrence Seaway System provided residents along the St. Lawrence River and the Great Lakes dramatically improved access to better markets, including international ones. In its first year of operation, more than twenty-five million tons of products traveled along the seaway.
The seaway's opening increased trade and production in several Ohio cities. Ashtabula, Cleveland, and Toledo experienced growth. Unfortunately, the long-term economic benefits of the Great Lakes St. Lawrence Seaway System have not met initial expectations. Due to ice forming on the waterway during winter months, the seaway remains open, on average, 260 days per year. The size of the canals also prohibits larger ships from using the watercourse. In 1979, the Great Lakes St. Lawrence Seaway System experienced its greatest use, with more than eighty million tons of products traveling along the seaway. In the waterway's first thirty years of existence, 160,000 ships from fifty different nations traversed the route. The Great Lakes St. Lawrence Seaway System remains operation today, although in 2004 it became known as HwyH2O.