The Grand Ethiopian Renaissance Dam, formerly known as the Millennium Dam and sometimes referred to as the Hidase Dam, is a gravity dam on the Blue Nile River in Ethiopia. The dam is in the Benishangul-Gumuz Region of Ethiopia, about 14 km (9 mi) east of the border with Sudan.

The Blue Nile is a river originating at Lake Tana in Ethiopia. It travels for approximately 1,450 km (900 mi) through Ethiopia and Sudan. Along with the White Nile, it is one of the two major tributaries of the Nile and supplies about 85.6% of the water to the Nile during the rainy season.