The region is made up of ten municipalities, Medellín being the most important, largest and the capital city of the Antioquia Department.

The metropolitan area was created in order to produce economic integration, projection, and planning for urban development in the cities over the Aburra Valley.

The total population of the ten cities and municipalities part of this metropolitan area is close to four million inhabitants.

The development of the Aburra Valley occurred in the 1930s after a rapid population growth that produced a conurbation of Medellín, Itagüí, Envigado, and Bello.

Medellín, as the capital of the Antioquia Department, main economic center and host of most of local government entities contributed to a rapid urban development which absorbed many corregimientos such as Robledo, La América, La Floresta, Guayabal, and Belén, among others.