The Carleton Island Royal Shipyard, operating from 1778 to 1788, was a crucial British military and logistical hub during the American Revolutionary War. Located on what was then known as Buck Island (renamed Carleton Island after Governor Sir Guy Carleton), this strategic site in the Thousand Islands region of the St. Lawrence River served several vital functions for the British.
Initially chosen over Cataraqui (present-day Kingston, Ontario) for its defensibility, Carleton Island became a key transshipment point for supplies moving between Montreal and the Great Lakes. Large vessels on Lake Ontario were not suited for the St. Lawrence, so goods were offloaded at Carleton Island and transferred to smaller boats.
The shipyard itself, known as Carleton Island Dockyard (or Schank's Harbor after British shipbuilder John Schank), was central to maintaining British naval supremacy on Lake Ontario. It built and maintained vessels for the Provincial Marine and Royal Navy, including the formidable warship Ontario, launched in 1780. Fort Haldimand, a partial octagon-shaped fort with bastions, ditches, barracks, and magazines, was constructed on the island to defend the naval station and shipyard.
Beyond its logistical and shipbuilding roles, Carleton Island also served as a base for military operations against American towns and a refuge for Loyalists fleeing persecution. Prominent Loyalists, including future politician Richard Cartwright and Molly Brant (sister of Joseph Brant), resided on the island, contributing to its merchant community.
However, with the close of the American Revolutionary War and the signing of the Jay Treaty, Carleton Island was ceded to the Americans. While the British initially maintained a presence, the island's importance declined. By 1785, government store transshipment was relocated to Kingston, and the naval yard itself was moved in 1788. Though technically ceded earlier, British control lingered until the War of 1812, after which the island transitioned to more peaceful pursuits like farming and tourism. Today, the ruins of Fort Haldimand are a testament to its significant, though relatively brief, period as a vital British outpost in the Thousand Islands.