The Jhelum rises at Verinag in Kashmir, runs through the valley, past Srinagar and through Wular lake, and down into Punjab to join the Chenab at Trimmu.
It is the Hydaspes of the Greek accounts, on which Alexander fought Porus in 326 BC in the only major battle of his Indian campaign. The site is somewhere near Jhelum or Jalalpur Sharif and has never been fixed.
The Lower Jhelum Colony was cut from it from 1901 and produced Sargodha. The Upper Jhelum Canal followed.
It is the westernmost of the five rivers of Punjab. The Sindh Sagar Doab, between it and the Indus, is the Pothohar plateau, which is Punjabi-speaking, was the heaviest army recruiting ground in the province, and saw the March 1947 killings.
Mangla dam, built between 1961 and 1967 under the Indus Waters Treaty settlement, holds it in Pakistan and displaced around 110,000 people.
The Jhelum was allotted to Pakistan under the Indus Waters Treaty of 1960 along with the Chenab and the Indus, with limited Indian use permitted.
The battle with Porus was fought during the monsoon at a crossing whose location is still argued over. No site has been established archaeologically.
Jhelum town and district are Pothohar country and were the heaviest recruiting ground in Punjab for the British Indian Army.