More than 450 million years ago, many imposing rivers furrowed the area, carrying to the sea tons of sandy and organic sediments. Eventually, these sediments rested at the bottom of the ocean to slowly form a rocky bed. When the earth's crust shifted, this seabed rose up as a huge plateau. Water, wind and weather slowly broke it apart into a series of islands.

The Mingan Islands is one of the prime sites for observing marine life in the St. Lawrence. From May through July, one can regularly observe breaching humpback whales, as well as surface feeding of the blue, fin, minke and humpback whales. Additionally, it is not uncommon to observe Atlantic white-sided dolphins, harbor and grey seals, harbor porpoises, and occasionally right whales, all of which come to prey on the swarms of copepods which live in these nutrient-rich waters.