As a biannual procedure, the IBGE once again updated the list of municipalities that comprise the Metropolitan Areas - RMs, Integrated Development Areas - RIDEs and urban agglomerations established by the states and Union, based on information of June 30, 2017. Since 2013, the IBGE updates the composition of the Brazilian RMs, RIDEs and Urban Agglomerations on its webiste on a biannual basis Other information on regional divisions can be accessed here.

This revision maintains the RMs and RIDEs published in the previous semester
Today, Brazil counts with 73 Metropolitan Areas, being Paraíba (12) the state with the biggest number, followed by Santa Catarina (9), Alagoas (8) and Paraná (8). The IBGE revision does not bring any change in the list of municipalities either of the Metropolitan Areas - RMs or Integrated Development Areas - RIDEs: that of Petrolina/Juazeiro, Greater Teresina and Federal District and Surroundings
According to the Federal Constitution of 1988, metropolitan areas and urban agglomerations are divisions established by state complementary laws, aiming at integrating the organization, planning and implementation of civil services of common interest. States are responsible for establishing metropolitan areas and urban agglomerations, according to Article 25, Paragraph 3 of the Federal Constitution.
Integrated Development Areas - RIDEs are established as administrative areas encompassing different Federation Units. RIDEs are created by specific laws, which list the municipalities that comprise them, as well as establish their operation structures and the interests of the participating political-administrative units. The creation of RIDEs is under the responsibility of the Union, according to Article 43, Paragraph 1 of the Federal Constitution.