The Derajat is the strip along the west bank of the Indus, Dera Ghazi Khan and Dera Ismail Khan, at the foot of the Sulaiman range where Punjab meets Balochistan.
It was part of Punjab province under the British and Dera Ghazi Khan remains part of Pakistani Punjab. Its speech is Saraiki and Balochi and its social organisation is tribal.
Ranjit Singh Ji's state took the Derajat, and Sikh governors administered it in the 1820s and 1830s.
The hill torrents, the rod kohi, that come off the Sulaiman range are the district's irrigation: floodwater spread over fields by earth embankments, a system unlike either canal or well irrigation and much older.
It is the poorest part of Pakistani Punjab by most measures.
Punjab as an administrative province included Saraiki, Balochi and Pashto-speaking country, and reducing it to the Punjabi-speaking central districts loses about a third of it.
The Indus itself is the belt's other water and it is barely used here, because lifting from the river needs pumps and the tract has never had the power to run them at any scale.
The tribal areas along the Sulaiman range were administered separately under British rule and the boundary between settled district and tribal territory ran through the belt.
Saraiki language politics and the demand for a separate southern province are strongest here, and they are an argument about what Punjab is.