Teresina is the capital and most populous municipality of the Brazilian state of Piauí. Located in north-central Piauí, approximately 366 km from the coast, it serves as a significant urban center with a population of 902,644 inhabitants. It ranks as the 19th largest city in Brazil and the 16th largest state capital in the country.
The city is notable for being the only capital in the Brazilian Northeast that is not situated on the shores of the Atlantic Ocean. Teresina forms a conurbation with Timon, a municipality in the neighboring state of Maranhão, creating an area with over 2.8 million inhabitants in its metropolitan region. The Parnaíba River, one of the largest rivers in the Northeast, serves as the only natural barrier separating Teresina from Timon.