In the southern parts of the Ethiopian Highlands once was located the Kingdom of Kaffa, a medieval and early modern state, whence the coffee plant was exported to the Arabian Peninsula.

The Ethiopian Highlands began to rise 75 million years ago,[7] as magma from the Earth's mantle uplifted a broad dome of the ancient rocks of the Arabian-Nubian Shield.

Most of the flows were tholeiitic, save for a thin layer of alkali basalts and minor amounts of felsic (high-silica) volcanic rocks, such as rhyolite.

Further, these mountains catch the precipitation of the monsoon winds of the Indian Ocean, resulting in a rainy season that lasts from June until mid-September.

The Ethiopian montane forests lie between 1,100 and 1,800 meters elevation, above the lowland grasslands and savannas, and extend to areas of similar habitat in Eritrea, Sudan, and Djibouti.

Weyna dega is a woodland found in moister and higher locations, dominated by the conifers Afrocarpus gracilior and Juniperus procera.

The lower portion of the Harenna Forest is a distinct woodland community, with an open canopy of Warburgia ugandensis, Croton macrostachyus, Syzygium guineense, and Afrocarpus gracilior, with wild coffee (Coffea arabica) as the dominant understory shrub.

However these hillsides have good fertile soil and are heavily populated, largely by farming communities, so most of the region has been converted to agriculture with a few areas of natural vegetation remaining.

Remaining woodland in the drier areas contains much endemic flora and primarily consists of the conifers Afrocarpus falcatus and Juniperus procera, often with the broadleaved Hagenia abyssinica.

The evergreen broadleaved forest of the Semien Mountains, between 2,300 and 2,700 meters elevation, is dominated by Syzygium guineense, Arundinarial, Juniperus procera, and Olea africana.

As the lower slopes of the mountains are so heavily populated, even the high altitude moorlands are affected by human interference, such as the grazing of livestock and even farming.

These slopes are home to a number of endemic wildlife species, including the endangered walia ibex (Capra walie) and the gelada baboon, whose thick fur allows it to thrive in the cooler climates of the mountains.

Birds include Rueppell's chat, the finch Ankober serin (Serinus ankoberensis), white-winged flufftail (Sarothrura ayresi), and blue-winged goose.

Other fauna in the area also includes aardvark, eagle, Egyptian wolf, gelada, secretarybird, Nubian ibex, and marabou stork and Ethiopian endemic species such as the shrew (Crocidura harenna), the narrow-footed woodland mouse (Grammomys minnae), and Menelik's bushbuck (Tragelaphus scriptus meneliki), which is a subspecies with long, dark fur.