Extension and limits. – Regular international treaties concluded in recent decades with the European powers dominating the neighboring territories (Italy, France, England) have almost exactly defined the borders. As for the Eritrean-Ethiopian border, which goes from Ombrega sul Setit to Daddato, in Danakil, 60 km away. from the coast of the Red Sea, the point where the borders of French Somalia converge, please refer to what is said in the Eritrean entry. The border with French Somalia was conventionally established by the Franco-Ethiopian treaty of March 20, 1897 with a line that encircles 100 km. away the bay of Tagiura. The border with British Somalia was established with the Addis Ababa (Addis Ababā) convention of May 14, 1897; that with Italian Somalia was conventionally fixed by the treaty of 16 May 1908, with a line that, starting from Dolo at the confluence of the Daua (Dawa) with the Ganale (Giuba), reaches the Uebi Scebeli at the border point with the tribe of theBaddi Addi (Bādi ‛Addä) which remains in Italy, while the territory of the tribes upstream from that of the Baddi Addi remains dependent on Ethiopia. Beyond the Uebi Scebeli the border heads north-east until it reaches the intersection of the Italian border with the English one. This border, rather vaguely indicated on the basis of ethnic divisions, has nevertheless never been defined on the ground. As for the Anglo-Ethiopian border from Ombrega sul Setit to Lake Rudolf, which divides Ethiopia from Anglo-Egyptian Sudan, and from Lake Rudolf to the confluence of the Daua with the Ganale, which divides it from the Kenyan colony, it was determined by treaties of 1902 and 1907; although the demarcation of the border on the ground, initiated on the side of the Kenyan Colony by the Gwynn mission, has not given officially definitive results for Ethiopia. Within these boundaries, not exactly determined everywhere, the area of Ethiopia can be considered to rise to about 1,100,000 sq km.
Physical Constitution. – According to Findjobdescriptions, Ethiopia is far from being a natural region. In its vast territory of irregular and bizarre shape, however, some main territorial divisions can be introduced, essentially determined by tectonics. A very wide mountainous region, or rather a very high plateau made in part very bumpy by the erosion of a dense hydrographic network, occupies the entire western part, namely Abyssinia proper, with the Tigrè, the Amhara, the Goggiam, and Scioa, and the western Galla regions, with Guma (Gumā), Limmu or Ennarea (Ennāryā), Gimma (Ǧimmā), Caffa, and Ghimira (Gimirā). This Abyssinian-caffino plateau, essentially formed by a large plateau of volcanic rocks of the Trappica series, on a base of Mesozoic and archaic crystalline sedimentary rocks, touches the highest known elevations on its eastern edge, where it is abruptly limited by a fracture escarpment, which overlooks the Danakil, the Hawash valley and the basins of the Galla lakes, on the other hand it slopes gently towards the West, that is towards the Sudan, where it descends at altitudes of 400 m. approximately in the valley of the Dinder and that of the Baro, at m. 407 to S., on the shores of Lake Rodolfo, and 518 to Lake Stefania. The plateau is divided into four large sectors: the Tigrè sector, between the Mareb and the medium Takkazè, reaches m. 3145, and more to S. in the region of Macallè m. 3235; the sector of the Amhara and of the Goggiam, between the middle Takkazè and the middle Abai, or more precisely between the parallel of Macallè and that of Ancober (Ankobar), touches on the eastern ridge m. 3411 in Amba Alagi, 4196 with the Abuna Iosef (Abuna Yosēf) not far from Lalibalà (Lālibalā) and 4000 m. with the Abuya Miedà; but the highest elevations of this sector and of the whole plateau are a little inland, in the Semien group (Ras Dascian, 4620 m) to the NE. of Gondar (v.semien) and in the neighboring groups: M. Guna (m. 4250) near Dabra Tabor, Amba Farit (m.3975) near Dessiè (Dassē), M. Ciokkè at S. del Lago Tana (m. 4154); the Scioa sector turns in a semicircle towards the SW. and has smaller shares, always towards the margin: Tedda Mariam (Magazag) near Ancober (m. 3603), Addis Alem (Addis ‛Ālam) near Addis Abeba (m. 3345), M. Dendi (m. 3210); finally the southern sector or Caffa-Ciamo sector is split by numerous and deep valleys in a maze of mountain groups, among which we will remember the M. Botor in the Ennarea (m. 2920), the M. Scialla near Girèn in the Gimma (m. 2945), Mount Hoda in the Limmu (m. 932), the Magi mountains (Māži; m. 2438). Between the Omo valley and the basins of the Galla lakes runs a series of reliefs that line up in the NNE.-SSW direction, with the Ancober ridge: they are the M. dei Guraghie (Gurāgē) and the M. Muggo, the M. dei Soddo exceeding 3000 meters and the M. Gughe to the West of Lake Regina Margherita and Lake Ciamo, to which 4200 m are attributed. in height. The series of depressions in which the middle course of the Hawash and the Galla lakes nest, unites, rather than divides, the Abyssinian and Caffino plateau and the Somali plateau, which faces it to the SE. Contrary to the previous one, this one has a steep escarpment in echelons, facing NW, and a gentle and regular slope that descends to the SE from the crest of that one, until it submerges in the Indian Ocean. The highest elevations of this Somali plateau are found as usual along the ridge, and are the M. dei Giam-Giam in the upper Daua, with altitudes of over 3000 m., The M. dei Sidamo (Sidāmō; M. Guramba, m. 3367), M. Cilalo (m. 3655), Kubsa (Qubsā; meters 3680), Cacca (Kakkā; m. 3820) and Galamo in the Alto Uabi, the M. di Laggio in Bāli on the right of this river; the Fagogi (m. 3256) and the Ciallanko mountains near Harar (m. 2569), after which the ridge continues to the West in English territory. The lowest points in this eastern region are Dolo sul Giuba (221 m) and Buslei on Uebi Scebeli (216 m).
The vast area, depressed and arid, which is limited to the west by the abyssinian plateau escarpment, to the south by that of the hararino plateau, to the east by the border of Eritrea, French Somalia and British Somalia, constitutes the third of the great Ethiopian regions and takes the name of Danakil or Afar (see danakil). It is a succession of large closed basins, occupied by salty lakes and their chalky and saline deposits, often below sea level (Alel Bad, −120 m.; L. Afreda, −140 m.), Alternating with volcanic cones and flows of the Aden series, already mentioned in part.