Dera Ghazi Khan was founded by Haji Khan which was called after the name of his son Ghazi Khan who died in 1494 A.D. Before the first Muslim invasion in the area now comprising the district there was only one town i.e. Mari, the rest of the country was un-inhabited. It was remarkably connected by tradition with Rasalu, the legendary hero and his opponent Raja Sirkap. Towards the mid of the 19th century (or in 1849) on conclusion of the second Sikh War, the district was annexed by the British. Adjustment in boundaries between D.G. Khan & Dera Ismail Khan districts took place between 1866-97 A.D.
The DG Khan District is bounded on the north by Dera Ismail Khan districts of NWFP and its adjoining Tribal Area, on the west by Musa Khel and Barkhan districts of Baluchistan Province, on the south by Rajanpur and on the east by Muzaffargarh and Leiah separating the latter two districts by river Indus.