The Gulf of Maine is one of the world's most biologically productive environments.The coastlines of Massachusetts, New Hampshire, Maine, New Brunswick, and Nova Scotia make up its western and northern boundaries. Its marine waters and shoreline habitats host some 2,000 species of plants and animals. Ocean currents control temperatures and bring nutrients and food to the plants and animals that occupy the rich undersea terrain.

The Gulf of Maine is a semi-enclosed sea bounded to the south and east by underwater banks. The map below shows the seafloor terrain of the Gulf of Maine. The darker blues represent deeper areas, and lighter blues indicate shallower depths. These contours were shaped by glaciers 10,000 to 20,000 years ago. Under the waters of the Gulf of Maine, valleys plunge to depths of 1,500 feet (500 meters) and mountains thrust up from the depths 800 feet (266 meters), almost reaching the surface.

The Gulf of Maine watershed encompasses much of Nova Scotia, New Brunswick, Maine, New Hampshire and Massachusetts, and a small portion of Quebec. The total land area of this watershed is 69,115 square miles, or 179,008 square kilometers. Only one of the six jurisdictions, Quebec, does not have Gulf of Maine shoreline, and only one of the six, Maine, is located entirely in the watershed. This large land area is divided among the states and provinces as follows:

	Land area in watershed		Percentage of total area
State or Province	Square miles	Square kilometers
Maine	33,215	86,027	100
New Brunswick	15,750	40,792	56
New Hampshire	6,500	16,835	70
Nova Scotia	7,550	19,555	36
Massachusetts	3,400	8,806	41
Quebec	2,700	6,993	0.45

Map of watershed (white area)

Click to learn more about habitats of the Gulf of Maine:

• Barrier banks and deep channel
• Banks and ledges
• Coastal habitats
• Deep basins
• The Gulf's currents
• Sheltered bays
• Tidal action