It is one of the four coastal municipalities in Piauí (besides Ilha Grande, Luís Correia, and Cajueiro da Praia), all of which make up the city's metropolitan area.

At that time, there was a charqueada owned by Domingos Dias da Silva, Portuguese founder of Porto das Barcas and pioneer in the region, mainly in the commercial and agricultural sectors.

The city is located on land Cenozoic Quaternary and has altitude of about 5 meters in areas of the urban center which is away from the coast.

Megathermal semi-humid tropical climate predominates in the region, with high rate of rainfall due to the mass action Equatorial Atlantic during the months from January to June.

[3] Second city in the state of Piauí, Parnaíba distinguished by beautiful landscape, marked by Carnaubais, and the relatively moderate commercial and industrial activity.

Tourism is gaining strength, and the city center of "rota das emoções" which is a tourist route between Lencois Maranhão, Parnaíba Delta Jericoacoara.

Starting on December 30, 2020, Azul airlines, the third largest airline carrier in Brazil, will fly every Sundays and Wednesdays straight (3 hours and 10 minutes) from Campinas (São Paulo) to Parnaíba (Piauí), these flights from Campinas (main Hub of Azul in Brazil) to Parnaíba will enable people from Lisboa, Miami, Orlando, Buenos Aires, Paris and southeast, mid-west, and south Brasil plus Manaus and Belém to arrive faster in Parnaíba Delta and Piauí cost much faster.

[citation needed] Two shopping centers, cinemas and bowling, and a theater are being erected in the city in the main boulevard, the Avenida São Sebastião.