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.

[2] In January 2014, Bulgaria started construction of a 30 km (19 mi) long security fence along its border with Turkey to contain a surge of migrants from the Middle East and North Africa.

Turkey's ambassador to Bulgaria Suleyman Gokce has expressed dissatisfaction with the border barrier adding that it creates discontent and gives reason to "reflect on the political message," that the fence is sending.

Prime Minister Boyko Borisov described the extension as "absolutely necessary," in order to prevent persons from illegally entering the European Union member state.

[6] The Bulgarian Parliament has decided to continue construction of the fence at the border with Turkey without launching a public procurement procedure because of the need to safeguard national security.