The Diamir District is a first-order administrative division of the Pakistani-controlled territory known as the Northern Areas and is the district in which the Karakoram Highway enters that territory from Pakistan's Khyber Pakhtunkhwa. The capital of the Diamir District is Chilas. In 2004, the Diamir District was reduced in size as a result of the creation of the new Astore District from Diamir's easternmost tehsil. (See map.)
The Diamir District is bounded by the Astore District in the east, Pakistan's Khyber Pakhtunkhwa in the southwest (separated by the Babusar Pass or Babusar Top), Neelum District of Azad Kashmir in the south, the Ghizar District in the north and northwest, and the Gilgit District in the north and northeast.
Before the Karakoram Highway was opened in 1978, the only road reaching Gilgit town from the south was a rough track north from Balakot to Babusar Pass (via Kaghan, Naran, Besal, and Gittidas) and farther north through Babusar Gah to Chilas. The road up to Besal is now in better condition, but from Besal to Babusar Pass, the road is still a rough track.