Demographics of Rio de Janeiro
Rio de Janeiro City is home to more than 6 million people, accounting for about 35% of the population of Rio de Janeiro State. Portuguese remains the most widely spoken language and Rio de Janeiro is the second city in the Portuguese speaking world.
Nilópolis
Nilópolis (, , ) is a municipality in Brazil, located in the Rio de Janeiro state's southwestern region, bordering São João de Meriti, Mesquita and Rio de Janeiro. It is the smallest municipality in Rio de Janeiro state, with a total area of 19.39 km². The population of 157,483 inhabitants living in an area of 9 km² and the remaining area corresponds to the Gericinó's Natural Park. Officially, the population density exceeds 8,120 inhabitants/km², but if calculated just 9 km² occupied, it becomes the most densely populated city in Brazil with more than 17.400 inhabitants/km². Currently, São João de Meriti has the highest population density, with 12,897 inhabitants/km².