Brahmani River, river in northeastern Odisha state, eastern India. Formed by the confluence of the Sankh and South Koel rivers in southern Bihar state, the Brahmani flows for 300 miles (480 km). It winds generally south-southeast past Bonaigarh and Talcher and then turns east to join northern branches of the Mahanadi River, which then empties into the Bay of Bengal at Palmyras Point. It is one of the few rivers that cut across the Eastern Ghats, and it has formed a minor gorge at Rengali, where a dam has been built.