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Persians are the main ethnic group of Iran and are the majority and dominant ethnic group of Iran. They also inhabit in neighboring countries particularly in Afghanistan, Tajikistan, and Uzbekistan. However, in these countries they are usually thought of as a sub-group and are referred to as Tajiks. Significant numbers of Persians also reside outside of these countries, with the largest communities found in the United States
http://en.wikipedia.org/wiki/Persian_people