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Ariel photo of a section of the Long Sault Parkway

This information was provided by the Parks of the St. Lawrence

April 22, 2025 - Updated Public Notice

Please be advised that the Long Sault Parkway will be closed to the public from April 25 to 27, 2025, to support Exercise TRILLIUM VENTURE, a large-scale military training operation taking place across Ontario. Parks of the St. Lawrence campgrounds and day-use areas along the Parkway will also be used during this time; however, these areas have not yet opened for the 2025 season. Please note that the St. Lawrence Marathon will also be taking place on Saturday, April 26, 2025, utilizing the full length of the Long Sault Parkway. The military exercise has been coordinated to ensure it will not interfere with the race.

Led by Joint Task Force Central (JTFC) and involving approximately 1,500 Canadian Armed Forces (CAF) members from the Army, Navy, and Air Force, this exercise will simulate a coordinated emergency response to a major air disaster.

During this time, residents and visitors may notice increased military activity in the region, including:

  • CAF vehicles on local roads
  • RCN and OPP boats on area waterways
  • RCAF helicopters in the skies over the Ottawa area and surrounding airspace

No weapons or ammunition will be present during the exercise.

As part of this partnership, the St. Lawrence Parks Commission has further assisted with Exercise TRILLIUM VENTURE by collaborating with their chainsaw training, enabling the military team to safely remove several trees identified as diseased and in need of removal.

The St. Lawrence Parks Commission is proud to be among the provincial, municipal, federal, and third-party partners contributing to this coordinated effort, including:
  • City of Cornwall
  • United Counties of Stormont, Dundas and Glengarry
  • South Stormont County
  • South Dundas County
  • South Glengarry County
  • North Stormont County
  • North Dundas County
  • Mohawk Council of Akwesasne
  • Raisin River Conservation Authority
  • Ontario Provincial Police / OBSARVA
  • Ontario Power Generation
  • Royal Canadian Mounted Police
  • Canadian Coast Guard
  • Canadian Border Services Agency

Please see attached information directly from the Canadian Armed Forces.

Thank you for your understanding and cooperation and the Long Sault Parkway will reopen to the public on Monday, April 28, 2025.