HMS Ontario (1780)

Shotline Diving Wreck Profile

• Name: HMS Ontario (1780)
• Type: 22-gun brig–sloop / Provincial Marine armed vessel
• Year Built: 1780
• Builder: Carleton Island (St. Lawrence River)
• Dimensions: Approx. 80 ft (26 m) length; beam ~25 ft (7.6 m); Depth of hold ~500 ft (150–160 m)
• Registered Tonnage:
• Depth at Wreck Site: 150 m / 500 ft
• Location: Southern Lake Ontario, between Niagara and Rochester (exact coordinates undisclosed)
• Number of Masts: 2

Wreck Location Map

Vessel Type

The HMS Ontario was a two-masted snow-rigged brig-sloop of the British Provincial Marine, armed with 22 cannons. Built at Carleton Island in 1780 during the American Revolutionary War, it served as a transport and patrol vessel on Lake Ontario, carrying troops, supplies, and dispatches between British posts.

Description

The HMS Ontario, a 22-gun brig-sloop of the British Provincial Marine, was lost in a fierce gale on October 31, 1780. Discovered in 2008 in an exceptional state of preservation, it is the oldest fully intact shipwreck in the Great Lakes and one of the most important maritime archaeological finds in North America.

History

On October 31, 1780, Ontario departed Fort Niagara bound for Oswego with an estimated 105–129 people aboard. A sudden, violent gale struck, capsizing and sinking her. No survivors were reported. This remains the single deadliest maritime disaster on Lake Ontario.

Significant Incidents

• October 31, 1780: HMS Ontario capsized and sank during a violent gale, resulting in the loss of an estimated 105–129 lives.

Final Disposition

In May 2008, Jim Kennard and Dan Scoville located the Ontario using side-scan sonar and confirmed the find with a remotely operated vehicle (ROV). The wreck sits upright on the lakebed, masts still standing, cannons in place, and even glass windows intact — preserved by the cold, oxygen-depleted waters at depth. The exact location is kept secret to protect the site.

Current Condition & Accessibility

The HMS Ontario is exceptionally well preserved; it remains upright on the lakebed with masts, cannons, and windows intact.

Resources & Links

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HMS Ontario is the oldest fully intact British warship ever found in the Great Lakes. Its discovery has deepened our understanding of 18th-century shipbuilding and the naval strategies of the American Revolutionary War. As a war grave and protected archaeological site, it stands as a monument to those lost and to the region’s maritime heritage.