Strandzha (also transliterated as Strandja and Stranja) is a mountain massif in southeastern Bulgaria and the European part of Turkey, in the southeastern part of the Balkans between the plains of Thrace to the west, the lowlands near Burgas to the north and the Black Sea to the east. Its highest peak is Mahyada (1031 m) in Turkey, while the highest point on Bulgarian territory is Golyamo Gradishte (710 m). The total area of the massif is approximately 10,000 km.
The climate of the area is considerably influenced by the Black Sea and is predominantly transitional to Mediterranean. Major rivers in the area are the Veleka (147 km long) and the border river Rezovska (112 km long). Strandzha Natural Park, established in 1995 in the Bulgarian part of the mountain, is the largest protected area in Bulgaria, embracing 1,161 km, or about 1% of the country's total territory. 50% of Bulgaria's flora can be observed in the park.
Inhabited by the Thracians in antiquity, Strandzha is an area with a large concentration of ruins of Thracian sanctuaries and sacrificial altars, dolmens and other archaeological objects.
The mountains were the site of the Bulgarian Preobrazhenie Uprising of 1903 crushed by Ottoman troops. The current Bulgarian-Turkish border in the region was established after the Balkan Wars of 1912-1913, when the northern part of Strandzha became part of Bulgaria.
Culturally, the Bulgarian part of Strandzha is known for the specific architecture that can be observed in Malko Tarnovo, Brashlyan and most other villages, the rich folklore and distinctive rituals, such as nestinarstvo (barefoot dancing on live coals), that preserve numerous pagan elements.