The Detroit River separates Windsor, Ontario. Canada, and Detroit Michigan, U.S.A..
It is one of the busiest rivers on the planet, but just a small part of the longest navigable waterway in the world. From the mouth of the St. Lawrence river, which empties into the Atlantic, to the Western end of Lake Superior, the largest of the Great Lakes of North America, it is 3,060 miles. A long way to paddle a canoe.