One of the great falicies about World War II is that no Axis powere ever occupied any part of the continental United States. In fact, the Japanese had occupied two of he Aleutian Islands, part of Alaska, early in the war. The islands of Attu and Kiska fell into Japanese hands in mid 1942.
Operation Cottage was the code name for the last operation of the Aleutian Island Campaign in which the Allies invaded Kiska island. Perhaps the most notable aspect of the operation was that just prior to the Allied invasion, the entire Japanese garrison had abandoned the island, taken off in stealth by submarines, leaving only empty fortifications and mined paths to traverse. Regardless, even with no actual Japanese on the island, the Allies suffered over 300 casualties.
The invasion of Kiska began on August 15, 1943. The invasion fleet, consisting of three battleships, two cruisers, and nineteen destroyers, bombarded Japanese positions prior to the initial landings which were first conducted by elements of the First Special Service Force in both landing zones, American and Canadian. Landing on D+1 would be the Canadian 13th Infantry Brigade, an element of the 6th Canadian Infantry Division. In the fog, Canadian and American troops promptly opened fire on each other, mistaking one another for Japanese troops, resulting in significant casualties for both sides. Over the next few days, many more Allied troops would go missing in action, die to enemy mines, or simply suffer from trench foot, marking the invasion effectively as an embarrassing event for Allied forces, though it did result in the end of the Aleutian Island Campaign.
Among the casualties were 71 aboard the USS Abner Read which struck a mine while patrolling the waters around Kiska. One unexpected find however, was the discovery of a dog nicknamed ‘Explosion’, which had survived for over a year since its owners, the American sailors captured by the Japanese marines in the initial landing, had been sent to POW camps. Following the events of Operation Cottage, the vast majority of personnel were evacuated out, with some staying behind to help construct new air facilities on the island.
Taken from: http://world-war-2.wikia.com/wiki/Operation_Cottage