Larus marinus, commonly known as the Great Black-backed Gull, is native to the northern parts of the Atlantic Ocean, including regions on both the eastern coast of North America and the western coast of Europe. Its distribution covers areas from Newfoundland and Labrador down to North Carolina in North America, and from Iceland, through the British Isles to the western coasts of Norway, with some populations spreading to inland lakes and rivers in these regions.

The Great Black-backed Gull inhabits coastal and marine environments. It typically resides in areas with access to large bodies of water, including oceanic coasts, estuaries, bays, and occasionally large reservoirs or lakes. The climate in these regions can be described as temperate to subarctic, depending on the exact location, with variations in temperature and precipitation patterns.

As a top predator and scavenger, the Great Black-backed Gull occupies a crucial ecological niche in its environment. It feeds on a variety of prey, including fish, smaller seabirds, carrion, and garbage, playing a role in controlling these populations and recycling nutrients. They are known for their adaptability to different food sources, a key factor in their widespread distribution across the northern Atlantic regions.