Place of Origin

The Son River or Sone of central India is the largest of the Ganga's southern tributaries orginates near Amarkantak in Madhya Pradesh

Length

784 kilometres (487 mi) long

Confluence

-

Description

The Son originates near Amarkantak in Madhya Pradesh, just east of the headwaters of the Narmada River, and flows north-northwest through Madhya Pradesh state before turning sharply eastward where it encounters the southwest-northeast-running Kaimur Range. The Son parallels the Kaimur hills, flowing east-northeast through Uttar Pradesh Jharkhand and Bihar states to join the Ganga just above Patna Geologically, the lower valley of the Son is an extension of the Narmada Valley, and the Kaimur Range ,an extension of the Vindhya Range. Dehri on sone is the major town situated on theSonRiver

Source:  http://en.wikipedia.org/wiki/Sone_River

Ecological significance 

The Son has been notorious for changing course, as it is traceable from several old beds near its east bank. In modern times this tendency has been checked with the anicut at Dehri, and now more so with the Indrapuri Barrage