this article is about the Brazilian city. For the animal, see piranha, for the band, see The Piranhas.

Piranhas is a historic city and municipality in the State of Alagoas, in the Northeast Region of Brazil. Located on the bank of the São Francisco River, just at the border with the State of Sergipe, Piranhas was founded in 1891and originally named Floriano Peixoto (in honor of the Army General who was one of the founders of the Republic and later elected President). It was initially named Porto de Piranhas, because a fisherman had caught some piranhas (a carnivore predator fish) there. In the 30s, Piranhas was attacked several times by the cangaceiros, bands of marauders and bandits commanded by the infamous Lampião, who frequently hid from the police in the rocky outcrops near the city.

• Population: 20,021 (2000)
• Area: 407 km²
• Elevation: 88 m
• Distance from the capital (Maceió): 291 km
• Climate: dry and hot, average annual temperature: 28 Celsius
• Economic activity: fishing, agriculture, cattle raising, ecotourism.

Its architecture is late Empire, Northeast style of constructions. Water sports such as catamarans, sailboats and canoes are available at river beaches and lakes, as well tours along the São Francisco using typical paddle steamers (gaiolas). Several waterfalls, the mighty and wide river itself, the semi-arid and rough caatinga, strange rock formations, and its river gorges are appreciated by tourists and trekkers for their natural beauty.

Piranhas can be reached by boat from several ports along the São Francisco, or by car, via a paved road from Maceió (AL-225).