Jacarezinho is a favela in Rio de Janeiro, with more than 60,300 residents living in an area of 40 hectares. It is located in the North Zone of the city, and borders the neighborhoods of Jacaré, Méier, Engenho Novo and Triagem. It is the third-largest favela in Rio de Janeiro, behind Rocinha and Complexo do Alemão. The favela expanded as the city industrialized, and it became the biggest favela in Rio de Janeiro by the mid-20th century, with a population of 23,000 in 1960. The crucial element in its growth was the industrial boom in the nearby Méier district after World War II, according to the historian Julio Cesar Pino, author of a book about the favelas of Rio de Janeiro.