Long Sault Parkway

Islands

The eleven islands associated with the parkway, listed from west to east, are:^[7][9]

• McLaren Island
• Woodlands Island
• Fraser Island
• Hoople Island
• Dickinson Island
• Heriot Island
• Vankoughnet Island
• Phillpotts Island
• Macdonell Island
• Snetsinger Island
• Mille Roches Island

Moulinette Island is connected to the island chain but is not considered part of the Long Sault Parkway.

Beaches

Mille Roches Beach is located on Mille Roches Island and is described by the St. Lawrence Parks Commission as the largest public beach along the St. Lawrence River corridor.^[10]

Woodlands Beach is located on Woodlands Island and includes a day-use and picnic area.

Both beaches occupy land that remained above the flood level following creation of Lake St. Lawrence.

Cycling and walking

The parkway forms part of the Great Lakes Waterfront Trail, a multi-use route extending along the Canadian shores of the Great Lakes and St. Lawrence River.

The route is open to cyclists and pedestrians, and connects with waterfront trails extending west toward Upper Canada Village and east toward Cornwall.^[11]

Scuba diving

The flooded landscape surrounding the parkway has made the area a destination for scuba diving.

Lock 21, situated underwater near Macdonell Island, is a surviving structure of the former Cornwall Canal. The lock was constructed during an enlargement of the canal in the late 19th century and was submerged beneath Lake St. Lawrence in 1958.

The St. Lawrence Parks Commission identifies Lock 21 as one of Canada's notable shore-access diving sites.^[8]

Remnants of former roads, canal works and other structures are also present underwater in parts of the region.

St. Lawrence power and navigation project

The Long Sault Parkway was created as a direct result of construction of the Moses-Saunders Power Dam and St. Lawrence Seaway during the 1950s.^[12]

For centuries, the Long Sault rapids formed a significant obstacle to navigation along the St. Lawrence River. Canal systems constructed during the 19th century allowed vessels to bypass the rapids, including the Cornwall Canal, but proposals to create a deeper international navigation channel and a hydroelectric power project developed during the late 19th and early 20th centuries.

The International Joint Commission became involved in efforts to coordinate development of the international section of the river. Plans repeatedly stalled in the United States during the 1930s and 1940s.

In 1951, the Canadian government announced that it was prepared to proceed with hydroelectric development and a navigation system largely within Canadian territory. The United States subsequently joined the project.

On June 7, 1954, the Supreme Court of the United States upheld approvals for the project, removing one of the final legal barriers to construction.^[13]

Ontario Hydro became responsible for much of the Canadian power-development work, while the International Joint Commission coordinated aspects of the international project.^[12]

Construction and relocation

On August 10, 1954, Canadian prime minister Louis St. Laurent, Ontario premier Leslie Frost, New York governor Thomas E. Dewey and other officials gathered at the community of Maple Grove to formally begin construction. Rather than turning a ceremonial shovel of soil, the officials detonated a dynamite charge.^[14]

The project required extensive relocation throughout the St. Lawrence Valley. Approximately 6,500 residents were displaced and ten communities in Ontario were submerged.^[4]

Many homes and other buildings were physically moved to the newly constructed communities of Long Sault and Ingleside or to Upper Canada Village. Other structures were demolished before flooding.

The project also affected the Mohawk community of Akwesasne. Ontario Power Generation and the Mohawk Council of Akwesasne reached a settlement concerning historical impacts associated with the power project in 2008.^[15]

The original site of the Battle of Crysler's Farm was also flooded. Its memorial was relocated to higher ground near Upper Canada Village.

Creation of the parkway

The Ontario-St. Lawrence Development Commission was established in 1955 to develop parkland and recreational facilities along the future shoreline.^[16]

Construction of the Long Sault Parkway was announced on March 1, 1956. The project was initially estimated to cost C$1.5 million.^[17]

Work began that June. McNamara Construction graded the future causeways while Davey Construction constructed the bridges.^[18]

Because construction occurred before flooding, bridges and causeways were initially built across dry farmland. Contemporary photographs showed bridges standing above fields that would later become channels of the St. Lawrence River.

Ontario Hydro began clearing approximately 20,000 acres (81 km²) of the Canadian flood zone during 1957.

On June 26, 1957, the Ontario Department of Mines announced names for the future parkway islands. The names commemorated early settlers, historical figures and communities that were to disappear beneath Lake St. Lawrence.^[19]

Inundation Day

July 1, 1958, became known locally as Inundation Day.

At approximately 8:00 a.m. EDT, 30 tons of dynamite were detonated to breach a cofferdam holding back the St. Lawrence River.^[4] Water began flowing into the cleared portions of the valley.

The reservoir continued filling during the following days. By July 4, much of the former landscape had disappeared beneath Lake St. Lawrence.^[20]

Hilltops left above the new water level became islands. The causeways and bridges constructed before flooding transformed them into the chain that forms the Long Sault Parkway.

The roadway itself was not immediately ready for public use. It opened in November 1958.^[2]

Beaches, campgrounds and other recreational facilities were progressively opened during 1959.^[21]

Engineering plan from June 1956 showing the proposed Long Sault Parkway before the surrounding land was flooded

2025–2027 revitalization

In July 2025, the Government of Ontario announced an investment of more than $82 million over four years in infrastructure operated by the St. Lawrence Parks Commission. The program included major work at Mille Roches Beach and Campground on the Long Sault Parkway.^[22][23]

The project includes new municipal water and wastewater connections between Long Sault and park facilities on Mille Roches and Snetsinger islands, replacing aging wells and septic infrastructure.^[24]

Reconstruction of the Mille Roches facilities began during the 2025–2026 period. Planned work includes accessible gender-neutral washrooms, new campground servicing, a new trailer dumping station, new changing facilities, outdoor rinse showers and a replacement canteen building with a waterfront patio.^[24]

Mille Roches Campground and the Mille Roches day-use area were closed for the 2026 operating season while the work proceeded. The St. Lawrence Parks Commission expected the renovated facilities to reopen in 2027.^[24]

The parkway itself remained open during the work, although temporary single-lane traffic restrictions were used near construction areas. Water and wastewater construction on the western portion of the parkway was scheduled to continue into 2027.^[25]