Jumna River, or Yamuna River, tributary of the Ganges, in Northern India. It begins in the Himalayas and is nearly 900 mi (1,400 km) long. Canals draining water from the Jumna irrigate about 12,000 sq mi (31,100 sq km) in central India. The cities of Delhi and New Delhi lie along the banks of the Jumna, and it flows close to Agra, site of the Taj Mahal. The Jumna joins the Ganges near Allahabad. Their confluence is considered sacred to Hindus.