Katnehia River rises in the swamps on the northern side of Basti District
, and flows in the south-east direction along the borders of Nagar East. It is the only tributary of the
on its left bank.
It joins with the Garehia River, which has its origin south of Rasulpur, and traverses along the borders of Nagar East and
Mahuli West. Turning south, the Katnehia merges with Kuwana River at Mukhlispur in Mahuli East.