Taiwan

Taiwan, also known as the Republic of China, was a pre-war country, and one of the rivals of the People's Republic of China. It is unknown if Taiwan was annexed by the People's Republic of China during the Resource Wars, or perhaps even before. It is likely however that it was a target in the Great War. Assuming the Republic of China managed to survive until the Great War, it would have been 165 years old.

In the cancelled Fallout: Extreme, imperial remnants from Taiwan retook mainland China, but this would be unlikely as the government of Taiwan is not a monarchy but a republic, hence the name.