Dobrich Province in the context of "Shumen Province"

Southern Dobruja or South Dobruja (Bulgarian: Южна Добруджа, romanized: Yuzhna 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.

Balchik (Bulgarian: Балчик Bulgarian pronunciation: [bɐɫˈt͡ʃik]; Romanian: Balcic, Turkish: Balçık) is a town and seaside resort on the Bulgarian Black Sea Coast in the Southern Dobruja area of northeastern Bulgaria. It is in Dobrich Province, 35 km southeast of Dobrich and 42 km northeast of Varna. It sprawls scenically along hilly terraces descending from the Dobruja plateau to the sea, and is often called "The White City" because of its white cliffs.

Kavarna (Bulgarian: Каварна [kɐˈvarnɐ], Greek: Καβάρνα) is a Black Sea coastal town and seaside resort in the Dobruja region of northeastern Bulgaria. It lies 42 kilometres (26 miles) northeast of Varna, 43 km (27 mi) from Dobrich, and 43 km (27 mi) south of the border with Romania. It is the principal town of Kavarna Municipality, part of Dobrich Province. As of December 2009, the town had a population of 11,397. A little yacht port, a fishing base, a spacious beach and a resort complex exist in the town. The landmark Cape Kaliakra is located a few kilometers to the east, as is the tiny beachfront resort of Rusalka. Three 18-hole golf courses with villa communities and marinas are being developed nearby, two of the courses are designed by Gary Player and one by Ian Woosnam.

During the 2000s, the town became famous with the annual Kaliakra Rock Fest featuring famous rock bands from around the world.

Balchik Municipality (Bulgarian: Община Балчик) is a municipality (obshtina) in Dobrich Province, Northeastern Bulgaria, located on the Northern Bulgarian Black Sea Coast in Southern Dobruja geographical region. It is named after its administrative centre - the town of Balchik.

The municipality embraces a territory of 523 km (202 sq mi) with a population of 19,331 inhabitants, as of 2018.