The Simien Mountain massif is one of the major highlands of Africa, rising to the highest point in Ethiopia, Ras Dejen (4620m), which is the fourth highest peak on the continent. The dramatic landscape of the Simien Mountains is the result of massive seismic activity in the area about 40 million years ago. Molten lava poured out of the Earth's core reaching a thickness of 3000m. Subsequent erosion over the millennia has left behind the jagged landscape of the Simien Mountains: gorges, chasms and precipices. The famous pinnacles - the sharp spires that rise abruptly from the surrounding land - are volcanic necks - the solidified lava and last remnants of ancient volcanoes.

The mountains are home to three of Ethiopia's larger endemic mammals: the walia ibex, the more common gelada baboons and the very rarely seen Ethiopian wolves.