Mexico City is located in Mexico.
Lake Texcoco ( Lago de Texcoco ) was a natural lake within the Anáhuac or Valley of 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 . It is located in the Valley of Mexico ( Valle de México ) , a large valley in the high plateaus at the center of Mexico , at an altitude of 2240 m . 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 .