The Beas rises at Rohtang and runs about 470 kilometres to join the Sutlej at Harike. It is the only one of the five rivers that lies wholly within India.
It is the Hyphasis of the Greek accounts, the river at which Alexander's army refused to go further in 326 BC and turned back. Where exactly that happened is not established.
Goindwal, Sultanpur Lodhi, Khadur Sahib and Kartarpur are all on or near it. The Kali Bein, which Guru Nanak Dev Ji is said to have entered at Sultanpur, is a tributary of it.
Pong dam holds it in Himachal. Harike, where it meets the Sutlej, is a Ramsar wetland and the main winter waterbird site in Punjab, with over a hundred thousand birds in some counts, and it is also where the Indira Gandhi canal to Rajasthan is taken off.
The Beas is the least dammed and the least polluted of Punjab's rivers, which is a relative statement.
Beas Kund below the Rohtang is the traditional source and the name is from Vyasa, the sage the Mahabharata is credited to, who is said to have made the pool there. The Sanskrit name is Vipasha, the unfettered, and the Greek form comes through that.
The Pong dam, completed in 1974, displaced tens of thousands in the Kangra valley. Its reservoir is a Ramsar site and a major wintering ground for birds.
The Beas Sutlej Link, finished in 1977, takes water from Pandoh through tunnels driven under the Dhauladhar to the Dehar power house on the Sutlej. Most of the flow above Pong now reaches the Sutlej by that route, and the river below Pandoh runs on what the link leaves in it.