I looked up "westernmost island in Alaska", and found out that it is called Attu Island. However, this island is in the Eastern Hemisphere and can therefore also be considered one of the easternmost points in the US and even the world.

However, the geometrically easternmost island is Semisopochnoi Island, near the 180th meridian. I wonder which island lies beyond it, and can claim the spot of westernmost island geometrically and be relatively close to that in terms of the International Date Line sense as well.

  • 3
    which island lays beyond it - in which direction? Note that the date line isn't on the 180 longitude here. Commented Dec 2, 2021 at 12:21
  • East of Semisopochnoi island. Commented Dec 2, 2021 at 12:24
  • 4
    If Attu is the westernmost island in Alaska, that will be closest to the date line (which goes to the west of it). You've confused the question by asking about the date line. Commented Dec 2, 2021 at 12:26
  • No I didn't. I said Attu is westernmost by that metric but there is another one that is westernmost by hemisphere. Commented Dec 2, 2021 at 12:33
  • I think readers could be misguided by the question in thinking that Alaska's island represent the easternmost and westernmost islands. They do not. The 180th meridian passes directly over Fiji. There is even an old news article on back in the day, when the official dateline was on the meridian. For New Year's Eve, some guy simply stepped across the bar in the hotel and thereby became the first person in recorded history to (announce that) he was celebrating the first moment of New Year's Day twice by simply stepping across a line in the bar.
    – Bruzote
    Commented Dec 3, 2021 at 17:24

1 Answer 1


The next island east of Semisopochnoi Island (longitudinally) is Amatignak Island which is at 179° 6' 31" W.

Wikipedia says

The southernmost point of Alaska is on this island, as well as the westernmost longitude of Alaska, the United States, and North America.

The International Date Line passes to the west of Attu, so Amatignak is further away from that than Attu or Semisopochnoi.

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