Based on information of December 31, 2015, the IBGE once again carried out the biannual update of the list of municipalities comprising the Metropolitan Areas (RMs), Development Integrated Regions (RIDEs) and Urban Agglomerations defined by the states and Federal Government. Since 2013, the IBGE biannually updates the composition of every Brazilian RM, RIDE and Urban Agglomeration in its website. Other information on the regional units can be accessed in the IBGE´s download channel, at the directory organizacao_do_territorio > analises_do_territorio  > municipios_por_regioes_metropolitanas > Situacao_2010a2019.

According to the Federal Constitution of 1988, Metropolitan Areas and Urban Agglomerations are units established by state complementary laws, aiming at the organization, planning and implementation of public services of common interest. As stated under Article 25, 3rd Paragraph of the Federal Constitution, States are responsible for establishing Metropolitan Areas and Urban Agglomerations.

On their turn, RIDEs are established as administrative areas that comprise different Federation Units. RIDEs are created through a specific legislation, listing the municipalities involved and establishing their operation and the interests of the participating political-administrative units. According to Article 43, 1st Paragraph of the Federal Constitution, the Federal Government is responsible for creating RIDEs.

Revision shows changes in 2 Metropolitan Areas

Currently, Brazil has 70 Metropolitan Areas. The state with the highest number of RMs is Paraíba (12), followed by Santa Catarina (11) and Alagoas (8). The current revision of the IBGE includes changes in two Metropolitan Areas: in Paraíba, Complementary Law no. 133 of September 23, 2015 explicitly included the municipality of Itabaiana in the RM that takes its name; in the RM of Natal (RN), the municipality of Ielmo Marinho was included.

This revision did not include any change in the lists of municipalities of the Urban Agglomerations, as well as in the three RIDEs: Petrolina/Juazeiro, Greater Teresina, and Federal District and Surroundings.

Previous revision showed changes in 6 RMs and one Urban Agglomeration

Based on information of June 30, 2015, the immediately previous revision showed changes in six Metropolitan Areas and in one Urban Agglomeration:

- In the RM of Greater São Luis (MA), the municipalities of Axixá, Cachoeira Grande, Morros, Presidente Juscelino were included on May 25, 2015;

- The RM of Apucarana (PR) was created on January 12, 2015, including the municipalities of Apucarana, Arapuã, Ariranha do Ivaí, Borrazópolis, Califórnia, Cruzmaltina, Faxinal, Godoy Moreira, Grandes Rios, Ivaiporã, Jardim Alegre, Kaloré, Lidianópolis, Lunardelli, Marilândia do Sul, Marumbi, Mauá da Serra, Novo Itacolomi, Rio Bom, Rio Branco do Ivaí, Rosário do Ivaí, São João do Ivaí and São Pedro do Ivaí;

- The RM of Campo Mourão (PR) was created on January 12, 2015, including the municipalities of Altamira do Paraná, Araruna, Barbosa Ferraz, Boa Esperança, Campina da Lagoa, Campo Mourão, Corumbataí do Sul, Engenheiro Beltrão, Farol, Fênix, Goioerê, Iretama, Janiópolis, Juranda, Luiziana, Mamborê, Moreira Sales, Nova Cantu, Peabiru, Quarto Centenário, Quinta do Sol, Rancho Alegre d'Oeste, Roncador, Terra Boa and Ubiratã;

- The RM of Cascavel (PR) was created on January 12, 2015, including the municipalities of Anahy, Boa Vista da Aparecida, Braganey, Cafelândia, Campo Bonito, Capitão Leônidas Marques, Cascavel, Catanduvas, Céu Azul, Corbélia, Diamante do Sul, Guaraniaçu, Ibema, Iguatu, Iracema do Oeste, Jesuítas, Lindoeste, Matelândia, Nova Aurora, Santa Lúcia, Santa Tereza do Oeste, Três Barras do Paraná and Vera Cruz do Oeste;

- The RM of Toledo (PR) was created on January 12, 2015, including the municipalities of Assis Chateaubriand, Diamante d'Oeste, Entre Rios do Oeste, Guaíra, Marechal Cândido Rondon, Maripá, Mercedes, Nova Santa Rosa, Ouro Verde do Oeste, Palotina, Pato Bragado, Quatro Pontes, Santa Helena, São José das Palmeiras, São Pedro do Iguaçu, Terra Roxa, Toledo and Tupãssi;

- The municipality of Jupiá was included in the Metropolitan Expansion Area of the RM of Extremo Oeste (SC) on January 15, 2015;

- The municipality of Laranjal Paulista was included in the Urban Agglomeration of Piracicaba (SP) on June 15, 2015.