Ethiopia-Sudan controversial border (Amharic: አወዛጋቢው የኢትዮ ሱዳን ድንበር) is a disputable border between Federal Democratic Republic of Ethiopia and the Government of Sudan since 19th century.[1] Ethiopia and Sudan share a very long boundary of 1600 km length. For the Sudan was under the colonization of British Empire, there was no clear border demarcation between Ethiopia and Sudan. But in 1902 Anglo-Ethiopian Treaty,[1] when Sudan was under British rule, British Empire demarcated a border by the help of Charles Gwynn, British royal engineer, without the presence of Ethiopian Empire.[2][3][4] Though it was not acceptable by the Ethiopia empire, the Ethio-Sudan colonial border is not clear since it mainly relies on natural land marks such as mountain, trees and rivers.[2]