The United States of America was a nation located on the Western Hemisphere. They were noted for their volatile interactions with the Mutant Race, primarily through the help of Trask Industries and Worthington Labs. They had tried several methods, including the Mutant Registration Act, the Leech Cure, the Mutant Wall and Camp X-Ray. Although the Sentinels appeared effective at first, they soon turned on the government and eradicated the United States of America.