Sennár lies within the northern limits of the tropical rains, which reach to Khartum, and fall between June and September. In this part of its course the Blue Nile rises from May to August, when the northern and western winds prevail, nearly coinciding with the cool and healthy season. But they are followed by the hot khaúsín from the south or the samúm (simoom) from the north-west charged with fine sand from the Libyan Desert. Still more dreaded are the miasmatic exhalations caused by the glowing sun playing on stagnant waters after the floods and giving rise to the “Sennar fever,” which drives the natives themselves from the plains to the southern uplands. The temperature, which rises at times to over 120° Fahr., is also very changeable, often sinking from 100° Fahr. during the day to under 60° Fahr. at night.

The soil, mainly alluvial, is naturally fertile, and wherever water and hands are available yields bounteous crops of maize, pulse, cotton, tobacco, sesame, and especially durra, of which as many as twenty varieties are said to be cultivated. The forest vegetation, mainly confined to the “Isle of Isles” and the southern uplands, includes the Adansouia (baobab), which in the Fazogl district attains gigantic proportions, the tamarind, of which bread is made, the deleb palm, several valuable gum trees (whence the term Sennári often applied in Egypt to gum arabic), some dyewoods, ebony, ironwood, and many varieties of acacia. These forests are haunted by the two-horned rhinoceros, the elephant, lion, panther, numerous apes and antelopes, while the crocodile and hippopotamus frequent all the rivers. The chief domestic animals are the camel, horse, ass, ox, buffalo (used both as a beast of burden and for riding), sheep with a short silky fleece, the goat, cat, dog, and pig, which last here reaches its southernmost limit. The tsetse fly appears to be absent, but is replaced in some districts by a species of wasp, whose sting is said to be fatal to the camel in the rainy season.

The “African Mesopotamia” is occupied by a partly settled partly still nomad population of an extremely mixed character, including representatives of nearly all the chief ethnical divisions of the continent. But the great plain of Sennár is mainly occupied by Hassanieh Arabs in the north, by Abu-Rof (Rufaya) Hamites of Beja stock (Robert Hartmann) in the cast as far as Fazogl, and elsewhere by the Funj (Fung, Fungheh), traditionally from beyond the "White Nile, and affiliated by some to the Kordofán Nubas, by others more probably to the Nilotic Negro Shillúks. These Funj, who have been the dominant race since the 15th century, have become almost everywhere assimilated in speech, religion, and habits to the Arabs. Nevertheless on their sacred Mount Guleh the traveller Pruyssenaere found them still performing pagan rites, while according to Marno the Búrúns, the southernmost branch of the race between the Berta highlanders and the Nilotic Dcnkas, are addicted to cannibalism. The Berta highlanders themselves (Jebalain, as the Arabs collectively call them) are of more or less pure Negro stock and number about 80,000, grouped in several semi-independent principalities. The " no-man’s-land” stretching north of Dar-Berta and east of the Tumat valley is also occupied by distinct nationalities, such as the Kadalos in the extreme north, the Sienetjos and Gumus in the east, here bordering on the Abyssinian Agaws, the Jabus and Gánti in the south. Most of these appear to be of Negro or Negroid stock; but the Sienetjos, said to he a surviving remnant of the primitive population of the whole country, are doubtless akin to the Sienetjos of Damot and Gojam in Abyssinia. They are certainly not blacks, and have a yellow or fair complexion, lighter than that of southern Europeans.

The Sennári people cultivate a few industries, such as cottonweaving, pottery, gold, silver, and iron work, matting, and leather work (camel saddles, sandals, &c.), noted throughout Sudan. But their chief pursuits are stock-breeding, agriculture, and trade,— exporting to Egypt and Abyssinia gold, hides, durra, sesame, gums, ivory, horses, and slaves. The chief centres of population, all on the Bahr-el-Azrak, are Fazogl (Fazoklo), now replaced by Famaka, at the Tumat confluence; Roséres, formerly capital of an independent state; Sennár, also an old capital, which gives its name to the whole region; Wod-Medineh at the Rahad confluence; and Khartum, just above the junction of the two Niles. A few miles above Khartum are the extensive ruins of Soba, former capital of the Funj empire, which at one time stretched from Wady Haifa to Dar-Berta and from Suakin to beyond Kordofán, but which was overthrown by Ismail Pasha in the year 1822.