The Aleutian Islands ( \ / əˈl ( j ) uːʃən \ / ; possibly from Chukchi aliat , `` island '' ) are a chain of 14 large volcanic islands and 57 smaller ones , forming part of the Aleutian Arc in the Northern Pacific Ocean , occupying an area of 6,821 sq mi ( 17,666 km ² ) and extending about 1,200 mi ( 1,900 km ) westward from the Alaska Peninsula toward the Kamchatka Peninsula , marking a line between the Bering Sea and the Pacific Ocean .
They are spread out over an area of 6,821 sq mi ( 17,666 km ² ) and go out about 1,200 mi ( 1,931 km ) west from the Alaska Peninsula toward the Kamchatka Peninsula .