The Simien Mountains are a component of the Ethiopian Highlands and are located in northern Ethiopia, northeast of Gondar in the Amhara region. They include the Simien Mountains National Park and are listed as a World Heritage Site. The mountains are made up of plateaus that rise to pinnacles and are divided by valleys. Ras Dejen, the tallest mountain in Ethiopia, rises to a height of 4,550 meters. Kidus Yared, the second-highest peak, is at 4,453 meters. Mount Biuat, at 4,437 meters, is another noteworthy peak.
With a length of 15.1 kilometers, Sof Omar Caves is the longest cave in Ethiopia. It was Africa's longest cave when it was measured in 1972. Since then, it has been surpassed by explorations in Madagascar (Ambatoharanana - Crocodile Cave 18.1 km) and Algeria (Rhar Bou Ma'za - the Tafna River Cave 18.4 km). The Weyib River (also known as the Gestro River) flows through it, and it is located east of Ginnir in the East Bale Zone of the Oromia Region in southeast Ethiopia.