Petrópolis is a city located in the state of Rio de Janeiro in southeastern Brazil. It is situated within a valley of the Órgãos Mountains, approximately 40 kilometres (25 mi) north of the city of Rio de Janeiro.
As of the 2022 Brazilian census, the municipality had a population of 278,881 inhabitants. It serves as the largest and most populous city in the Fluminense Mountain Region, while also holding the region's highest Gross Domestic Product and Human Development Index.