Two-storey squared timbered defensive structures built in 1813. They protected troops from small arms fire and light artillery while allowing them to return fire through loopholes. There were 13 blockhouses constructed in the Toronto area between 1793 and 1838. These are the only two surviving examples. When Fort George, near Niagara, was reconstructed, the measurements of these blockhouses were used in the reconstruction of the ones at Fort George.