The Ganga originates as Bhagirathi from Gangotri Glacier, Uttarakhand at an elevation of 3,892 m. 

• Many small streams comprise the headwaters of the Ganga. The important among these are Alaknanda, Dhauliganga, Pindar, Mandakini and Bhilangana. 
  • At Devprayag, where Alaknanda joins Bhagirathi, the river acquires the name Ganga. It traverses 2525 km before flowing into the Bay of Bengal. 
• The Ganga is formed from the 6 headstreams and their five confluences. 
  • Devprayag: Confluence of Bhagirathi river and Alaknanda river. 
  • Rudraprayag: Confluence of Mandakini river and Alaknanda river. 
  • Nandaprayag: Confluence of Nandakini river and Alaknanda river. 
  • Karnaprayag: Confluence of Pindar river and Alaknanda river. 
  • Vishnuprayag: Confluence of Dhauliganga river and Alaknanda river. 
• The Bhagirathi, considered to be the source stream, rises at the foot of Gangotri Glacier, at Gaumukh. It finally empties into the Bay of Bengal. 
• Major Tributaries of the Ganga River, 
  • Left Bank Tributaries: Ramganga, Gomti, Ghaghara, Gandak, Burhi Gandak, Koshi, Mahananda. 
  • Right Bank Tributaries: Yamuna, Tons, Karamnasa, Sone, Punpun, Falgu, Kiul, Chandan, Ajoy, Damodar, Rupnarayan. 
• The Ganga flows out of the hills and into the plains at a point where it meets the Yamuna in Allahabad. 
• Delta and Outflow 
  • After a journey of around 2,510 kilometres, the Ganga River merges with the Brahmaputra River in Bangladesh, forming the Padma River. 
    • The Padma River then joins the Meghna River and flows into the Bay of Bengal through the Meghna Estuary.