In the north the date line turns to the east through the Bering Strait and then west past the Aleutian Islands in order to keep Alaska and Russia on opposite sides of the line . This is to keep it in agreement with the date of the rest of those countries . This keeps Russia which is north and west of the Bering Sea and the United States ' Alaska which is east and south of the Bering Sea , on opposite sides of the line in agreement with the date in the rest of those countries .