Answer: Ghaghara
Notes: Chapra city is situated on the banks of Ghaghara river. It joins the Ganga river at Revelganj which is a town in Chapra district of Saran division. The total length of Ghaghara river up to its confluence with the Ganga river at Revelganj in Bihar is 1080 Km. It is the largest tributary of the Ganga river by volume and the second longest tributary of the Ganga river by length after Yamuna river.
