Southern Dobruja

Southern Dobruja
Южна Добруджа/Добруджа (Bulgarian)
Dobrogea de Sud/Dobrogea Nouă (Romanian)
Historical region of Southeastern Europe
1913–1940

Map of Bulgaria and Romania with Southern Dobruja or Cadrilater highlighted in yellow. Northern Dobruja is highlighted in orange.
Area 
• 1913
7,412 km2 (2,862 sq mi)
• 1940
7,412 km2 (2,862 sq mi)
Population 
• 1913
286,000
• 1940
400,000 (before population exchange)
History 
10 August 1913
7 September 1940
Political subdivisionsProvinces
Preceded by
Succeeded by
Kingdom of Romania
Kingdom of Bulgaria
Today part of Bulgaria

Southern Dobruja or South Dobruja (Bulgarian: Южна Добруджа, romanizedYuzhna Dobrudzha or simply Добруджа, Dobrudzha; Romanian: Dobrogea de Sud or Dobrogea Nouă, lit.'New Dobruja'), also the Quadrilateral (Romanian: Cadrilater), is an area of north-eastern Bulgaria comprising Dobrich and Silistra provinces, part of the historical region of Dobruja. It has an area of 7,412 square km and a population of 358,000.

It is historically noteworthy as a point of contention in Bulgarian-Romanian relations. Part of Bulgaria between 1878 and 1913, the region was annexed by Romania in the Treaty of Bucharest (1913), targeted by Bulgaria during World War I (1914–18), and subsequently remained Romanian until 1940, when Bulgaria regained control in the Treaty of Craiova, which went along with a compulsory population exchange. Southern Dobruja has been part of Bulgaria since 1940.