The Gulf of Maine, a unique ‘sea within a sea’ up to 1,500 feet deep, is sometimes called “New England’s own ocean.” It occupies about as much space in the water as the State of Maine does on land. The gulf, however, extends way beyond Maine — its watershed of about 70,000 square miles also includes areas in Massachusetts, New Brunswick, New Hampshire, Nova Scotia, and a small part of Quebec. It stretches from Cape Cod to Nova Scotia’s Cape Sable Island, and includes the Bay of Fundy, home to the highest tides (30 to 50 feet) in the world.

The Gulf of Maine Area program at the University of Southern Maine describes  the gulf by saying that, in contrast to “the gently sloping, low-lying lands laced with tidal rivers, marshes and bays” of America’s east coast from Florida to New York, this “steeper New England and maritime Canada coast is characterized by rocky shorelines, hundreds of harbors, and thousands of islands made of ledge, or upturned bedrock.” The Gulf of Maine is influenced by the Labrador Current instead of the Gulf Stream, making its water much colder and more full of nutrients than the U.S. southern Atlantic coast.

It’s home to 52 species of commercially harvested fish and shellfish, most famously the lobster. In all, a recent scientific study found, the Gulf of Maine contains 3,317 different species of fish, birds, mammals, deep-water coral, and microscopic plants, with hundreds or maybe thousands of species as yet undiscovered. At the same time, its edges are largely unpopulated by people, except for a few metropolitan areas like Boston, Portland, and Saint John, New Brunswick.

About 40 years ago, Canada and the U.S. began a dispute over access to the rich fishing grounds in the Georges Bank area of the Gulf of Maine, and in October 1984 the World Court in The Hague, Netherlands, set the current national boundaries.

Fun Fact: The highest tide ever recorded in the Bay of Fundy, during a cyclone in 1869, was just over 55 feet.