Bulgaria–Greece border

mountain range in southeastern Balkans

thumb|290px|right|Map of the river

1919 treaty

Belasica (Macedonian and Bulgarian: , also translit. Belasitsa or Belasitza, Ottoman Turkish: بلش Turkish: Beleş), Belles (, Bélles) or Kerkini (, Kerkíni;), is a mountain range in the region of Macedonia in Southeastern Europe, shared by northeastern Greece (about 45%), southeastern North Macedonia (35%) and southwestern Bulgaria (20%).

river in Bulgaria and Greece

peak located in Belasica mountains in the region of Macedonia

mountain in southwestern Bulgaria and northern Greece

highest peak of Belasitsa

Stargach (, ), also known as Sturgach or Stargač, is a border mountain, situated between south-western Bulgaria in the Blagoevgrad Province and northern Greece in the Drama region. It is a part of the Rhodope Mountains, sitting east of Slavyanka Mountain and south of the Pirin Mountains.

The Erythropotamos (, meaning "red river") or Luda reka (, meaning "mad river") is a river in southern Bulgaria (Haskovo Province) and northeastern Greece (Evros regional unit). Its Turkish name was Kızıldelisu. Its source is near Mega Dereio. It flows into the Maritsa (Evros) near Didymoteicho.

Fylakio (Greek: Φυλάκιο) is a village in the Evros regional unit of northeast Greece. Fylakio is in the municipal unit of Kyprinos. In 2021 the population was 867 for the community, including the villages Ammovouno and Keramos. It is located on the right bank of the river Ardas, about halfway between Ivaylovgrad (Bulgaria) and Edirne (Turkey).