Ecatepec, (Spanish [ekateˈpek] (help·info) once officially Ecatepec de Morelos, is a city and municipality in the State of Mexico. Both are usually known simply as "Ecatepec". The city is practically co-extensive with the municipality, with the city's 2005 population of 1,687,549 being 99.9% of the total municipal population of 1,688,258. The provisional population at the 2010 Census was 1,658,806. The city forms the most populous suburb of Mexico City (Ciudad de México) and the 15th-most-populous suburb in the world. It's also Mexico's 2nd most populous municipality (after Itzapalapa of CDMX).