A sea of northwest Russia, an inlet of the Barents Sea. It was the principal outlet for Muscovite seagoing trade during the 16th century. Sea, extension of the Arctic Ocean, northwestern Russia. Almost landlocked, it is connected to the more northerly Barents Sea by a long, narrow strait known as the Gorlo. It covers an area of approximately 35,000 sq mi (90,000 sq km) and has a maximum depth of 1,115 ft (340 m). Rivers, including the Northern Dvina and Onega, flow into it. An important transportation route, it remains navigable year-round with the help of icebreakers in winter. Arkhangelsk is one of the principal ports