Nova Iguaçu is a city in southeast Brazil in the Baixada Fluminense region of Rio de Janeiro state. It was the state's second largest city until Mesquita was split off, and now is the fourth largest after São Gonçalo and Duque de Caxias. The city is named after the Iguaçu River that runs through it and empties into Guanabara Bay. It lies northwest of the city of Rio de Janeiro, on the limits of the metropolitan area.