 Based on the surveys taken in the summers of 1820 and 1821, and guided by the Commission's two principles that the boundary would not divide islands and that the number of islands would be apportioned equally between the two countries, in November and December 1821, commissioners agreed to grant St. Joseph Island and Cockburn Island to Canada and Drummond Island, which lies between them, to the United States.According to the US Census Bureau, the township has a total area of , of which is land and , or 48.23%, is water.The island is dominated by forest, with cliffs on the eastern side, which are part of the Niagara Escarpment.