Regiunea București (București/Bucharest region) was one of the newly established (in 1950) administrative divisions of the People's Republic of Romania, copied after the Soviet style of territorial organization.
The capital of the region was Bucharest, and at first, its territory comprised an area similar to the nowadays Ilfov and Giurgiu counties. In 1952 it assimilated the dissolved Ialomița (without rayons Fetești, to Constanța region, and Urziceni, to Ploiești region; both taken in 1960) and Teleorman regions, reaching an area slightly smaller than nowadays Ialomița, Călărași, Ilfov, Giurgiu and Teleorman counties.
București region had as neighbors:
1950–1952: East: Ialomița region; South: People's Republic of Bulgaria; West: Teleorman; North: Argeș and Prahova regions.
1952–1960: East: Constanța region; South: People's Republic of Bulgaria; West: Craiova region; North: Pitești, Ploiești and Galați regions.
1960–1968: East: Dobrogea region; South: People's Republic of Bulgaria; West: Oltenia region; North: Argeș, Ploiești and Galați regions.
1950–1952: București, Giurgiu, Mihăilești, Crevedia, Răcari, Snagov, Brănești, Oltenița, Vidra.
1952–1960: București, Giurgiu, Mihăilești, Crevedia, Răcari, Snagov, Brănești, Oltenița, Vidra, Slobozia, Călărași, Lehliu, Vida, Alexandria, Zimnicea, Vârtoapele, Roșiori de Vede, Drăgănești, Turnu Măgurele.
1960–1968: București, Giurgiu, Mihăilești, Crevedia, Răcari, Snagov, Brănești, Oltenița, Vidra, Slobozia, Călărași, Lehliu, Vida, Alexandria, Zimnicea, Vârtoapele, Roșiori de Vede, Drăgănești, Turnu Măgurele, Fetești, Urziceni.
