The Pothohar plateau and the Salt Range were held for centuries by Gakhar and Janjua clans, tribal groups that were never fully subordinated by any Delhi power and were dealt with by treaty as often as by conquest.
Sher Shah built Rohtas specifically against the Gakhars, who had supported Humayun. The fort's scale is a measure of how seriously they were taken.
The Janjuas held the Salt Range and the Khewra salt workings.
Under British rule the same tracts became the heaviest army recruiting grounds in Punjab, and the martial races policy formalised what those clans had been doing anyway.
This is the northern Punjab that Indian Punjab lost completely in 1947, along with its dialect, its landscape and its history, and it is barely mentioned in anything written about Punjab on the Indian side.
Rohtas, built between 1541 and 1548, is the largest surviving fort of its period in the subcontinent and is on the world heritage list. It never saw the siege it was built for.
The Gakhars held the Pothohar under the Mughals as a subordinate power and were reduced by the Sikh state in the early nineteenth century, when Gujrat, Rawalpindi and the Salt Range were annexed.
Khewra's salt has been worked since at least the Mughal period and the mine is now among the largest in the world. The other Salt Range workings at Warcha and Kalabagh are of the same antiquity.