Paraíba or Paraíba do Sul (dŏ sōl) [key], river, c.650 mi (1,050 km) long, rising as the Paraitinga in the Serra do Mar, São Paulo state, SE Brazil. It flows southwesterly to a point NE of São Paulo city where it makes a hairpin turn and continues in a northeasterly direction through the state of Rio de Janeiro to the Atlantic Ocean near Campos. Below Três Rios it flows through a gorge on the Rio de Janeiro–Minas Gerais border. Its beautiful valley forms a rich agricultural region (site of Brazil's first commercial coffee plantation) as well as a major industrial center of Brazil. The river is used for irrigation, transport, and power generation.