Abyssinia (Arab. Habesh, signifying a mixture of peoples), a country of eastern Africa, lying S. W. of the Red sea. Its boundaries are not very accurately defined, especially as the name is frequently applied to a much greater extent of territory than that included in Abyssinia proper, which was formerly said to comprise the three important states of Tigre, Amhara, and Shoa, but from which Shoa has been excluded by some modern geographers. According to Keith Johnston, however, it extends from lat, 7° 40' to 16° 40' 1ST., and from lon. 34° 20' to 43° 20' E. On the N. and N. W. it is bordered by Nubia and Sennaar, while southward and eastward lie the Galla and Somali countries and Adal. The Samhara land separates Abyssinia proper from the Red sea, which is nowhere less than 90 m. distant from the frontier. According to M. d'Abbadie, the country is called Ethiopia by the natives, who properly employ the word Abyssinia to denote that portion of the population, for the most part professedly Christian, who have lost all idea of tribal differences. Its maximum length is upward of 600 m. and maximum breadth nearly as much; but these estimates are probably approximate, and as the area of the country depends upon them, it cannot be accurately stated.

The population is believed to be from 3,000,000 to 5,000,000. - Considered with reference to its physical geography, Abyssinia is an extensive, elevated, and irregular table land, consisting of a series of plateaux of various altitudes, which rise into isolated groups and ranges of flat-topped mountains. This table land runs nearly due N. and S., and slopes from its highest ridge toward the Red sea on one side and the interior of the continent on the other, so as to form an eastern and a western watershed. Toward the swamps and plains of Sennaar and Nubia the descent from this high region is gradual, but it is very abrupt on the east, the seaward slope being about twelve times greater than the opposite slope toward the Nile. The average elevation of the plateaux, which rise terrace-like and with gradually increasing elevation from N. to S., is between 7,000 and 8,000 ft. Among them, forming river beds sometimes thousands of feet below the general surface of the surrounding territory, wind ravines and gorges of extreme depth, which are among the most striking natural features of the country.

Mr. Clements R. Markham, who accompanied the British military expedition to Magdala, classifies the Abyssinian highlands as follows: 1, the region drained by the affluents of the river Mareb; 2, the region drained by those of the Tacazze and Atbara; 3, the region drained by those of the Abai. The first of these is in Tigre, and includes a considerable portion of northern Abyssinia. Here the average altitude of the plateaux is 9,000 ft. above the level of the sea. They enclose numerous extensive valleys, which, although many hundred feet lower, are none of them at an elevation of less than 7,000 ft. A peculiarity of the valleys here is that valley hills rise from their level tracts, just as mountains rise from the plateaux above. The principal summits of this region are Mt. Sowayra, 10.328 ft., and Arabi Tereeki, near Senate, 8,560 ft. The next great physical division of the table land comprises the drainage basin of the Tacazze and Atbara rivers. The loftiest district of this region is the rich agricultural plain of Haramat, 8,000 ft. above the ocean level.

In the N. AY. part, of Amhara, which is included in this division of the highlands, the country is lower, not exceeding 6,000 ft. of average elevation; but the province of Sem-yen contains the highest mountains in Abyssinia, of which the most important peaks are the Abba Jarrat, in lat. 13° 10' N., 15,088 ft, and Mt. Buahat, in lat. 13° 12' N., 14,362 ft. E. of these are the Harat hills and Wadjerat range. The third clearly defined region is that watered by the tributaries of the Blue Nile, comprising the greater portion of Amhara or the former kingdom of Gondar, with an altitude varying in different districts from 5,000 to 7,000 ft. on the plateaux, and attaining a height of 11,000 ft. in the Talba-Waha mountains. The Wadela and Dalanta plateaux, near Magdala, with an elevation exceeding 9,000 ft., are in the W. portion of this region, the river bed of the Jitta, 3,500 ft. deep, running between them. The steep scarped rock of Magdala itself rises to a height of 9,050 ft., its summit being a flat plain 2 1/2 m. long and half a mile wide. - The only important rivers of the country which flow toward the Red sea are the Ragolay, in the north, a perennial stream which loses itself in the sand before reaching the coast, and the Hawash in the south, which forms a portion of the boundary between Abyssinia and Adal, and is likewise absorbed in the swamps or deserts on its path to the ocean.

All the great Abyssinian rivers belong to the Nile basin. Of these the Mareb is the most northern. It rises in the district of Hamasen, flows S. and W. around Serawe, and thence in a N. W. direction through the Nubian province of Taka. In the rainy season its waters reach the Atbara, but during the remainder of the year they disappear in the sand. The Tacazze rises in Lasta from a spring which was first caused to gush forth from the rock, according to tradition, by a blow from the hand of Menilek, son of the queen of Sheba. Its name signifies "the terrible." Flowing northwesterly, it enters, or properly receives, the Atbara at Tomat, in Nubian territory. It is a rapid and impetuous stream, dashing down rocky falls and between lofty precipices with a turbulence well denoted by its name. Further S. is the Abai, the celebrated Nile of Bruce, although the Bahr-el-Azrek or true Blue river rises in the Galla country under the name of the Dedhesa, and the Abai is in reality only its largest tributary. The latter rises S. of the Tzana lake, and making a northward circle through it, turns southward and joins the Bahr-el-Azrek near lat. 11° N. This lake, also called the Dembea, is situated in a grain-producing region of great fertility, at a height of 6,110 ft. above the level of the sea.