National Historic Site of Canada is a small, uninhabited island in the Niagara River in the province of Ontario, managed by Parks Canada. Modern terms make Navy Island feel practically forgotten. The Navy Island is a small overgrown island in front of the bay of Errol Flynn Marina. Niagara's first British shipyard was located on Niagara Falls, Ontario Island of Navy Island. Navy Island is a small, uninhabited island in Ontario, Canada.