PARNAHIBA, a town of Brazil, province of Piauí, stands on the E. bank of the River Parnahiba, about 15 miles above its mouth, and 300 N. of Oeiras. It has broad unpaved streets. It is the only seaport in the province; but is not capable of admitting vessels of above 150 tons burden. Some trade is carried on in hides and cotton. The court-house and custom-house are the chief public buildings. Pop. of the district, about 10,000.