Bulgarian_border_barrier
Bulgaria–Turkey border
International border
The Bulgaria–Turkey border (Bulgarian: Българо-турска граница, romanized: Būlgaro-turska granitsa,Turkish: Bulgaristan–Türkiye sınırı) is a 513 km (319 mi) long international border between the Republic of Bulgaria and the Republic of Turkey. It was established by the Treaty of San Stefano in 1878 as an inner border within the Ottoman Empire between Adrianople Vilayet and the autonomous province of Eastern Rumelia. The current borders are defined by the Treaty of Constantinople (1913) and the Bulgarian–Ottoman convention (1915). The border was reaffirmed by the Treaty of Lausanne ten years later, though Bulgaria was not a party to the latter treaty as it had earlier ceded to Greece that part of its border with Turkey which was modified by the Bulgarian-Ottoman convention.