Hudson Strait is an arm of the sea connecting the Atlantic Ocean with Hudson Bay and Foxe Channel and separating Baffin Island from the Ungava Peninsula of Québec. The eastern gap is between Cape Chidley, at the northern tip of Labrador, and Resolution Island. There are 250 km of open sea across Ungava Bay and the strait trends northwest from Cape Hopes Advance to Cap de Nouvelle-France and then westerly to Cap Wolstenholme. Across the western gap is a group of 3 islands: Mill, Salisbury and Nottingham. The strait is never completely frozen over, and open water adds heat and moisture to the air, creating precipitation, cloud and fog. Resolution Island is one of the foggiest places on Earth, with fog reported an average of one day in 2. The "insurance date of entry" into the strait is July 23, but icebreakers extend the sailing season.

Hudson Strait provides access by sea to the heart of Canada and has been used commercially for 3 centuries, chiefly in connection with the fur trade. Hudson's Bay Company vessels have used it since 1670. Navigation of the strait is not intricate; the route is wide and free from shoals. However, fog, current and the tidal stream made it tricky for early sailing vessels. The Norse almost certainly knew the route. Martin Frobisher mistakenly entered the strait in 1578, but Henry Hudson - for whom it is named - was the first European known to have explored it and followed it into the bay.