7. Midway Atoll (no prior sovereign state, briefly claimed by Hawaii Kingdom)
Midway Atoll was uninhabited but claimed by the Kingdom of Hawaii in 1867, then taken over by the U.S. government. Its key location made it strategically important, especially during WWII. The Battle of Midway, fought from June 4-7, 1942, marked a turning point in the Pacific theater, with the U.S. Navy achieving a decisive victory over the Japanese fleet (britannica.com).
