The Bering Sea is separated from the Gulf of Alaska by the Alaska Peninsula. It covers over two million square kilometers, bordered on the east and northeast by Alaska, on the west by Russia's Siberia and Kamchatka Peninsula, on the south by the Alaska Peninsula and the Aleutian Islands and on the far north by the Bering Strait. The Strait connects the Bering Sea to the Arctic Ocean's Chukchi Sea. Bristol Bay is the part of the Bering Sea which separates the Alaska Peninsula from mainland Alaska. The Bering Sea is named for Vitus Bering, a Danish navigator in Russian service, who in 1728 was the first European to systematically explore it.