Where the St Lawrence River tumbles out of Lake Ontario on the US/Canada border, an archipelago of over 1,800 granite islands litters the waterway creating a beautifully scenic landscape. Windswept and draped with native pines the islands are home to opulent historic mansions, whose turrets jut above the treeline, and luxurious cottages and estates which are the current day retreats of the Canadian elite. One particular landmark is the slightly incongruous Boldt Castle, a six storey, 120 room, Rhineland-style structure which resides over Heart Island, a common photo stop on the various boat tours which weave through the waters.

This area is also a busy marine highway, and the secluded bays once provided the ideal hiding place for villains and vagabonds running from the law or trying to sneak across the international border. However, the geography creates a natural obstacle course with its many rocks and shoals and so a number of passenger boats, paddle-steamers and freighters have come to a watery end on these straits, making it one of the best fresh-water shipwreck diving destinations in the world.

The two main towns that top and tail the seaway here are Kingston and Gananoque. Each has its own charm and interesting heritage – indeed Kingston was once the capital of the ‘United Provinces of Canada’ until that title was moved to Ottawa – and either is well placed as a stopping off point for those travelling between Toronto and Ottawa or Montreal.