Ploiești

Ploiești (UK: /plɔɪˈɛʃti/ ploy-ESH-tee, US: /plɔːˈjɛʃt(i)/ plaw-YESHT-ee, Romanian: [ploˈjeʃtʲ]), formerly spelled Ploești, is a city and county seat in Prahova County, Romania. Part of the historical region of Muntenia, it is located 56 km (35 mi) north of Bucharest.

The area of Ploiești is around 60 km² (23 sq mi), and it borders the Blejoi commune in the north, Bărcănești and Brazi communes in the south, Târgșoru Vechi commune in the west, and Bucov and Berceni communes in the east. According to the 2021 census, Ploiești is the tenth most populous city in the country with a population of 180,540.

The city grew beginning with the 17th century on an estate bought by ruler Michael the Brave from the local landlords, gradually replacing nearby Wallachian fairs of Târgșor, Gherghița, and Bucov. Its development was accelerated by heavy industrialisation during the mid-19th century, with the world's first large-scale petroleum refinery being opened between 1856 and 1857. Following massive exploitation of the oil deposits in the area, Ploiești earned the nickname of "the Capital of Black Gold". In the present, a significant part of its economic activity is still based on oil processing, the city having three large refineries and other industries related to this branch.

Ploiești is also an important transport hub, linking the capital with the regions of Transylvania and Moldavia. The city has direct access to Prahova Valley, one of the most important alpine tourism areas in Romania.