Biledulgerid (Bheladal Dsherid = country of dates) was formerly a country in Northern Africa, south of Mount Atlas, bounded on the north by Tunis, on the west by Algiers and the Sahara, on the east by Tripoli, supposed to be about 180 miles square.
Contemporary account
Berbers lived here, along with Black people. A large proportion of the young men are destroyed by the change of climate to which they are thus exposed, as also by bad nourishment and epidemic fevers. Certain parts of this country, called Dara, Tasilet and Segelmesse, belong to Morocco; to Algiers belongs Wadreag, and to Tunis Tozer. Gaelernes, WelledSidi and Mosselemis are independent. Little is known of the customs, laws, &c, of the inhabitants.
One late 18th century source (William Carey, "An Enquiry Into the Obligation of Christians to Use Means for the Conversion of the Heathens") gave the dimensions of Biledulgerid as 2,500 miles in length and 350 miles in breadth with a population of 3.5 million. The country's religions are listed as "Mahometans, Christians, and Jews."