The Sankaraparani River originates on the western slope of Gingee Hill in Viluppuram District of the State of Tamil Nadu. It has two sources, one in the Pakkammalai hills and one in the mountains of Melmalayanur. They join near Thenpalai village to form the main river. Sankaraparani is also known as Varahanadi or Gingee River.
River Sankaraparani, flows to the east. The Annamangalam surplus joins near Melacheri. Then the river turns south in eastern part of Singavaram village and then flows east again. Second tributary Nariyar Odai joins Sankaraparani near Uranithangal village.
Near Vallam village, the river turns southeast to flow toward of Rettanai, Nedimozhiyanur, towards Veedur Dam. The third tributary Thondiar joins near Vidur. The Vidur reservoir across Sankaraparani is situated just below.
From Vidur reservoir, Sankaraparani flows southeast. Pambaiyar tributary joins near Radhapuram. Then Sankaraparani enters Puducherry Union Territory at Manalipet. Pambai tributary joins Sankaraparani near Sellipet.
Then Guduvaiyar River, the last tributary joins near Boat House. At this point, Sankaraparani is also called Chunnambar. From here it flows for 2 kilometres (1.2 mi) before draining into Bay of Bengal at Paradise Beach.
The total length of the river is 78.5 kilometres (48.8 mi). Of the total length, 34 kilometres (21 mi) flows in Puducherry.
Sankaraparani river has six tributaries namely:
The only distributary of Sankaraparani is Ariyankuppam River that branches near Thirukanchi.
There is a history that there was once great flooding of this river. The exact timing of the flood may need experts in history to tell us. However, the two proofs are: (1) The fossil park at Tiruvakkarai is about 1-2 km away from the river and located on a hillock. The ASI maintained park mentions that there was a great flood once that would have washed away all the logs of trees on the hillock which have been preserved as fossils since then.