There was only one battle in World War II that took place on US soil, and it wasn't where you would expect!

In 1942, the US military was concerned that Japan would be able to launch long distance air attacks on the continental United States from the small islands the occupied in Alaska.

As a result, in May, 1943, the United States and the Empire of Japan squared off on the Island of Attu for battle.

This is a significant battle for two reasons: First, it is the only battle to take place on US territory, and second, it was the only battle fought between the US and Japan that was in Arctic conditions!

If you were mislead by reading that this was a battle for an island and thought it was part of the South Pacific island hopping that the US did, think again. The island is part of Alaska, and is in the far end of Alaska's 'tail.'The conditions and the fighting were brutal.

The battle ended with over 2,850 dead Japanese and only 29 captured prisoners of war, meaning 99% of the Japanese soldiers on the island were dead.

(Source)