Although they do not contribute to the original acronym,
Mauá,
Ribeirão Pires,
Rio Grande da Serra (as they were an extension of the municipality of Santo André, before the division) and Diadema are also part of the region. The
Billings Reservoir bathes 6 of the 7 municipalities in the region, except São Caetano do Sul. The 7 municipalities together make up an area of 825 km², and have a population of over 2.5 million inhabitants (
IBGE estimate for 2007). ==Municipalities==