A river is a natural watercourse, usually of fresh water, flowing towards an ocean, a lake, a sea, or another river. Rivers form part of the hydrological cycle. This is a list of rivers in India. Rivers that flow into the sea are geographically, along the coast starting from the Bay of Bengal in the east, moving along the Indian coast southward to Kanyakumari, then northward along the Arabian Sea. Tributary rivers are listed hierarchically in upstream order: the lower in the list, the more upstream.