1. Sudan CIA Factbook
  [By CIA THE WORLD FACTBOOK]
Religions:
Sunni Muslim, small Christian minority
Population:

34,206,710
country comparison to the world: 36
note: includes the population of South Sudan (8,260,490); demographic data includes South Sudan (July 2012 est.)

 

2.Sudan Info
 [By U.S. Library Of Congress] 

The coming of Islam gradually changed the nature of Sudanese society and facilitated the division of Sudan into northern and southern halves, one Arab, the other, African. In the sixteenth century, the Ottoman Turks, governors of Egypt, claimed Nubia as a dependency but exerted little authority beyond the Nile. Meanwhile, in central Sudan, a new state called Funj arose with its capital at Sannar on the Blue Nile. The Funj checked the
expansion of the Arabs, in the process becoming devout Muslims themselves. In the west, the Fur people formed the state of Darfur and similarly adopted Islam. Both states engaged in the
slave trade with Egypt.