[1][2] The archdiocese is one of the largest in the world, with over four million Catholics, surpassed only by Kinshasa, Guadalajara, São Paulo, Puebla de los Ángeles, Santiago de Guatemala, and Milan.

Prior to 2019, the archdiocese was the largest in the world, with nearly 8 million Catholics.

In September 2019, Pope Francis approved the division of the archdiocese, erecting three new suffragan dioceses from its territory: Azcapotzalco, Iztapalapa, and Xochimilco.

Today, the archdiocese's territory comprises most of Mexico City, with the exception of the three new dioceses, each of which is coextensive with its eponymous borough.

The cathedra of the archdiocese is found within the Metropolitan Cathedral in Mexico City.