Teresina is the capital and most populous municipality in the Brazilian state of Piauí. Being located in north-central Piauí 366 km from the coast, it is the only capital in the Brazilian Northeast that is not located on the shores of the Atlantic Ocean. With 902,644 inhabitants, Teresina is the 19th largest city in Brazil, and the 16th largest state capital in the country. Together with Timon in the neighbouring state of Maranhão, it forms a conurbation with a population of about 2,729,527 inhabitants; the entire metropolitan region of Teresina has over 2,893,729 inhabitants. The only natural barrier that separates Teresina from Timon is the Parnaíba river, one of the largest in the Northeast.