The São Paulo Macrometropolis (Portuguese: Macrometrópole de São Paulo) or São Paulo Megalopolis (Portuguese: Megalópole de São Paulo), also known as Expanded Metropolitan Complex (Portuguese: Complexo Metropolitano Expandido), is a Brazilian megalopolis that emerged through the existing process of conurbation between the metropolitan areas located around the Greater São Paulo, with more than 30 million inhabitants, or 74 percent of São Paulo State's population, and is one of the most populous urban agglomerations in the world.
Beyond the Greater São Paulo, the megalopolis encompasses the metropolitan areas of Campinas, Baixada Santista, Sorocaba, Vale do Paraíba e Litoral Norte, Jundiaí and Piracicaba. The total population of these areas added to the state capital exceeds 31.5 million inhabitants, or about 75% of the population of the entire state of São Paulo.
The metropolitan complex is the only urban cluster (of agglomerations) of its kind in South America and covers an area of approximately 53 thousand square kilometers, connecting 174 municipalities and retains much of the industrial and economic output of the country.
The urban sprawl resulted from decades of conurbation, economic shifts, and a change in population preferences, with people increasingly favoring the interior over the saturated capital.
Although the first signs of conurbation appeared in Porto Ferreira (along the Anhanguera highway) and São Carlos (along the Washington Luís highway), the Macrometropolis officially begins in Pirassununga and extends through Leme, Araras, Rio Claro and Limeira; beyond the last of these cities, there are no longer any green spaces separating the urban areas.