Also known as The Imperial City, is a municipality in the Southeast Region of Brazil, located 68 kilometres (42 mi) northeast of Rio de Janeiro. The town’s name (“city of Peter”) honors Pedro II, the last Emperor of Brazil, who is entombed there at the Cathedral of Saint Peter of Alcantara. The city was the summer residence of the Brazilian Emperors and aristocrats in the 19th century, and was the official capital of the state of Rio de Janeiro during the First Brazilian Republic, between 1894 and 1902.

Nestled among the forested hills of the Serra dos Órgãos, in the valley of the Quitandinha and Piabanha rivers, Petrópolis is a popular winter holiday spot. Besides the climate and surroundings, the main attraction is the former Summer Palace of the last Brazilian Emperor, which is now the Imperial Museum, specializing in Imperial history and memorabilia.

Petrópolis is home to the National Laboratory for Scientific Computing, a research unit of the Ministry of Science and Technology of the Brazilian Federal Government.