Aleutian_Islands The Aleutian Islands (possibly from Chukchi aliat, "island") are a chain of more than 300 small volcanic islands forming a volcanic arc in the Northern Pacific Ocean, occupying an area of 6,821 sq mi (17,666Alaska Peninsula toward the Kamchatka Peninsula. Crossing longitude 180°, they are the westernmost part of the United States (and by one definition the easternmost; see Extreme points of the United States).