Welland Canal in the context of "Great Lakes Waterway"

The St. Lawrence Seaway (French: la Voie Maritime du Saint-Laurent) is a system of rivers, locks, canals and channels in Eastern Canada and the Northern United States that permits oceangoing vessels to travel from the Atlantic Ocean to the Great Lakes of North America, as far inland as Duluth, Minnesota, at the western end of Lake Superior. The seaway is named for the St. Lawrence River, which flows straight from Lake Ontario to the Atlantic Gulf of St. Lawrence. Legally, the seaway extends from Montreal, Quebec, to Lake Erie, and includes the Welland Canal. Ships from the Atlantic Ocean are able to reach ports in all five of the Great Lakes via the Great Lakes Waterway.

The St. Lawrence River portion of the seaway is not a continuous waterway; rather, it consists of several stretches of navigable channels within the river, a number of locks, and canals along the banks of the St. Lawrence River to bypass several rapids and dams. A number of the locks are managed by the St. Lawrence Seaway Management Corporation in Canada, and others in the United States by the Great Lakes St. Lawrence Seaway Development Corporation; the two bodies together advertise the seaway as part of "Highway H₂O". The section of the river from Montreal to the Atlantic Ocean is under Canadian jurisdiction, regulated by the offices of Transport Canada in the Port of Quebec.

St. Catharines is the most populous city in Canada's Niagara Region, the eighth largest urban area in the province of Ontario. As of 2021, St. Catharines has an area of 96.20 square kilometres (37.14 sq mi) and 136,803 residents. It lies in Southern Ontario, 51 kilometres (32 mi) south of Toronto across Lake Ontario, and is 19 kilometres (12 mi) inland from the international boundary with the United States along the Niagara River. It is the northern entrance of the Welland Canal. St. Catharines carries the official nickname "The Garden City" due to its 1,000 acres (4 km) of parks, gardens, and trails.

St. Catharines is between the Greater Toronto and Hamilton Area (GTHA) and the Canada–U.S. border at Fort Erie. Manufacturing was the city's dominant industry, as noted by the heraldic motto, "Industry and Liberality". General Motors of Canada, Ltd., the Canadian subsidiary of General Motors, was the city's largest employer, a distinction now held by the District School Board of Niagara. THK Rhythm Automotive, formerly TRW, operates a plant in the city, although in recent years, employment there has shifted from heavy industry and manufacturing to services.

The Niagara River (/naɪˈæɡərə, -ɡrə/ ny-AGG-ər-ə, -⁠grə) flows north from Lake Erie to Lake Ontario, forming part of the border between Ontario, Canada, to the west, and New York, United States, to the east. The origin of the river's name is debated. Iroquoian scholar Bruce Trigger suggests it is derived from a branch of the local Neutral Confederacy, referred to as the Niagagarega people on several late-17th-century French maps. George R. Stewart posits that it comes from an Iroquois town named Ongniaahra, meaning "point of land cut in two."

The river, occasionally described as a strait, is approximately 58 kilometres (36 mi) long and includes the Niagara Falls. Over the past 12,000 years, the falls have moved roughly 11 kilometres (6.8 mi) upstream from the leading edge of the Niagara Escarpment, creating a gorge below the falls. Today, the diversion of the river for electricity generation has significantly slowed the rate of erosion. The total elevation drop along the river is 99 metres (325 ft). The Niagara Gorge, downstream from the falls, includes the Niagara Whirlpool and additional rapids.

Air draft (or air draught) is the vertical distance from the surface of the water to the highest point on a vessel. This is similar to the deep draft of a vessel which is measured from the surface of the water to the deepest part of the hull below the surface. However, air draft is expressed as a height (positive upward), while deep draft is expressed as a depth (positive downward).

National Historic Sites of Canada are places that have been designated by the federal Minister of the Environment on the advice of the Historic Sites and Monuments Board of Canada (HSMBC), as being of national historic significance. Parks Canada, a federal agency, manages the National Historic Sites program. As of November 2023, there were 1,005 National Historic Sites, 171 of which are administered by Parks Canada; the remainder are administered or owned by other levels of government or private entities. The sites are located across all ten provinces and three territories, with two sites located in France (the Beaumont-Hamel Newfoundland Memorial and Canadian National Vimy Memorial).

There are related federal designations for National Historic Events and National Historic Persons. Sites, Events and Persons are each typically marked by a federal plaque of the same style, but the markers do not indicate which designation a subject has been given. For example, the Rideau Canal is a National Historic Site, while the Welland Canal is a National Historic Event.

The Events of National Historic Significance, also called National Historic Events (French: Les événements d'importance historique nationale), are events that have been designated by Canada's government, on the advice of the national Historic Sites and Monuments Board to the Minister of Environment and Climate Change, as being defining actions, episodes, movements or experiences in Canadian history. To be designated, an event must have occurred at least forty (40) years previous; events that continue into the more recent past are evaluated on the basis of what occurred at least 40 years ago. As of November 2025, there are 523 National Historic Events that are already recorded.

Related federal designations exist for National Historic Sites and National Historic Persons. Events, Sites, and Persons are each typically marked by a federal plaque, but the markers do not indicate which designation a subject has been given. The Welland Canal is an Event, while the Rideau Canal is a Site. The cairn and plaque to John Macdonell does not refer to a National Historic Person, but is erected because his home, Glengarry House, is a National Historic Site. Similarly, the plaque to John Guy officially marks not a Person, but an Event—the Landing of John Guy.

Persons of National Historic Significance (National Historic People) (French: Personnes d'importance historique nationale (personnages historiques nationaux)) are people designated by the Canadian government as being nationally significant in the history of the country. Designations are made by the Minister of the Environment on the recommendation of the Historic Sites and Monuments Board of Canada. Approximately 70 nominations are submitted to the board each year. A person is eligible to be listed 25 years after death, but Prime Ministers may be designated any time after death. Parks Canada administers the program, and installs and maintains the federal plaques commonly erected to commemorate each person, usually placed at a site closely associated with them. The intent is generally to honour the person's contribution to the country but is always to educate the public about that person.

Canada has related programs for the designation of National Historic Sites and National Historic Events. Events, Sites, and Persons are each typically marked by a federal plaque, but the markers do not indicate which designation a subject has been given. The Welland Canal is an Event, while the Rideau Canal is a Site. The cairn and plaque to John McDonell (Aberchalder) does not refer to a National Historic Person, but is erected because his home, Glengarry House, is a National Historic Site. Similarly, the plaque to John Guy officially marks not a Person, but an Event—the Landing of John Guy.