Mexico City is located in Mexico.
Mexico City , or the City of Mexico ( Ciudad de México , [ sjuˈða ðe ˈmexiko ] ; abbreviated as `` CDMX '' ) , is the capital and most populous city of Mexico . The city was responsible for generating 15.8 % of Mexico 's Gross Domestic Product and the metropolitan area accounted for about 22 % of total national GDP . The city was originally built on an island of Lake Texcoco by the Aztecs in 1325 as Tenochtitlan , which was almost completely destroyed in the 1521 siege of Tenochtitlan , and subsequently redesigned and rebuilt in accordance with the Spanish urban standards .