São Luís is the capital and largest city of the Brazilian state of Maranhão. The city is located on Upaon-açu Island or Ilha de São Luís, in the Baía de São Marcos, an extension of the Atlantic Ocean which forms the estuary of Pindaré, Mearim, Itapecuru and other rivers. Its coordinates are 2.53° south, 44.30° west. São Luís has the second largest maritime extension within Brazilian states. Its maritime extension is 640 km. The city proper has a population of some 1,108,975 people. The metropolitan area totals 1,605,305, ranked as the 15th largest in Brazil.

Alcântara is a Brazilian municipality in the state of Maranhão. The city has a population of 22,112 (2020) and an area of 1458 km2. The municipality is 30 km away from the state's capital, São Luís.