The Mareb River (or Gash River), is a river flowing out of central Eritrea which partly forms a natural frontier between Eritrea and Ethiopia.

According to the Statistical Abstract of Ethiopia for 1967/68, the Mereb River is 440 kilometers long. Its headwaters rise north of Amba Takara in central Eritrea, on the landward side of the eastern escarpment within 80 km of Annesley Bay on the Red Sea. It flows south, bordering Ethiopia, then west through western Eritrea to reach the Sudanese plains near Kassala. Unlike the Setit or Takazze river which flows out of Ethiopia and also forms a natural border with Eritrea, the waters of the Mareb do not reach the Nile, but dissipate in the sands of the eastern Sudanese plains. Location of the Red Sea Image:Red Seaimage. ... Kassala is the capital of the state of Kassala in northeastern Sudan. ... The Atbarah River in northeast Africa rises in northwest Ethiopia, approximately 50 km north of Lake Tana and 30 km west of Gondar. ... The Nile (Arabic: ‎, translit: , Ancient Egyptian iteru) is a river in Africa, often regarded as the longest river on Earth, although some sources claim the Amazon in South America is longer. ...

The Mareb is dry for much of the year, but like the Takazze is subject to sudden floods during the rainy season; only the left bank of the upper course of the Mareb is in Ethiopian territory. Its main tributaries are the Obel on the right bank (in Eritrea) and the Sarana, Balasa and 'Engweya Rivers on the left (Ethiopia).

The Mareb was important historically as the boundary between two separately governed regions in the area: the land of the Bahr negash (Tigrinya "kingdom of the sea", also known as Medri Bahri or "land of/by the sea") to the north of the river, and the Tigray to the south. The territories under the Bahr negash extended as far north as the Red Sea coast, and as far south (and west) as Shire^[1] and the capital was at Debarwa in modern Eritrea, about 20 miles south of Asmara. Tigrigna (or ትግሪኛ) is a Semitic language spoken in Eritrea, where it is the official language, and in parts of Ethiopia and Israel. ... Location of the Red Sea Image:Red Seaimage. ... Shire, also known as Inda Selassie, is a town in the Tigray region of Ethiopia, lying west of Aksum. ... Debarwa is a market town with a population of about 25 000 in central Eritrea, about 25 km south of the capital Asmara. ... Asmara Asmara (formerly Asmera) is the capital city and largest settlement in Eritrea, home to a population of around 579,000 people. ...

References

1. ^ Daniel Kendie, The Five Dimensions of the Eritrean Conflict 1941 – 2004: Deciphering the Geo-Political Puzzle. United States of America: Signature Book Printing, Inc., 2005, pp.17-8.