Petroșani (Romanian pronunciation: [petroˈʃanʲ]; Hungarian: Petrozsény; German: Petroschen) is a city in Hunedoara County, Transylvania, Romania, with a population of 31,044 as of 2021.

After Romania joined the Allies of World War I in 1916, Romanian troops attacked the town during the Battle of Transylvania.

The Romanian occupation, however, did not last long: the united Austro-Hungarian and German troops regained control of the town shortly, in which guerrilla warfare, led by the local Viktor Maderspach, played an important role.

The population experienced massive growth only in the 20th century during the communist government, as many workers were brought in from other parts of the country.

[5] At the 2002 census, 83.3% of the city's inhabitants were Romanian Orthodox, 7.2% Roman Catholic, 3.7% Reformed, 2.2% Pentecostal, 0.8% Greek-Catholic, and 0.9% belonged to another religion.