Muntenia is a historical region in southern Romania, part of Wallachia. Its limits are: to the north the Carpathian mountains (which delineate it from Transylvania), to the west Olt River (separating it from Oltenia), to the south and east the Danube River (which delimits it from Bulgaria and Dobrogea), and to the northeast the rivers Milcov, Putna and Siret (beyond which Moldova is located).
Muntenia includes the following counties and administrative units: Bucharest, Dambovita, Arges, Braila, Buzau, Giurgiu, Calarasi, Ialomita, Ilfov, Prahova, Teleorman. The segments lying to the east by the Olt River in the counties of Valcea and Olt, as well as the southern part of Vrancea County (south of Milcov) are also part of the historical region of Muntenia.
The Dobrogea region comprises the south-eastern part of Romania and is delimited by the Danube Delta in the north-east, the Macin Mountains to the north, the Black Sea to the east and the border with Bulgaria to the south. The surface of Dobrogea is approx. 21,200 sq km and is inhabited by approximately 972,000 inhabitants. The territory of Dobrogea is Romania's oldest territory, the Macin Mountains formed more than 600 million years ago (proof of the proterozoic green shale of the Casimcea plateau).
Geological drilling has brought to the surface rocks and sediments even older, of about 1.6 billion years.