The Port of Thunder Bay is located at the head of the Great Lakes/St. Lawrence Seaway System, a dynamic navigable waterway that stretches 3700 kilometres into the heart of the North American continent.A oneway voyage through the Seaway to Thunder Bay takes five days with ships 228.6 metres in length, 23.8 metres in width with a draft of 8.2 metres being elevated some 180 metres through 16 of the most efficient locks in the world. more... See more text