Ponnaiyar River in the context of Chengam

Penna (originally known as Penneru, also known as Pinakini, Penneru, Penner, Pennar, Pennai) is a river of southern India. After originating from Nandi hills, it flows as two different streams, one in North and South directions. The Penna rises in the Nandi Hills in Chikkaballapur District of Karnataka state, and runs north and east through the states of Karnataka and Andhra Pradesh to empty into bay of bengal in Andhra Pradesh. It is 597 kilometres (371 mi) long, with a drainage basin covering 55,213 km: 6,937 km in Karnataka and 48,276 km in Andhra Pradesh. Along with this main stream is another stream south towards Tamil Nadu with the name Then Pennai or south Pennar which further moves towards the east to empty into the Bay of Bengal. The Penna river basin lies in the rain shadow region of Eastern Ghats and receives 500 mm average rainfall annually.

Nandi Hills (Anglicised forms include Nandidurg and Nandydoorg) is an ancient hill fortress built by the Ganga dynasty in the Chikkaballapur district of Karnataka state. It is now a locality situated 10 km from Chickballapur town and approximately 60 km from Bengaluru. The hills are near the town of Nandi. In traditional belief, the hills are the origin of the Arkavathy river, Ponnaiyar River, Palar River, Papagni River and Penna River. Watching the sunrise at Nandi Hills is popular with tourists. The second SAARC summit was held at Nandi Hills in 1986.

Toṇḍaimaṇḍalam, also known as Toṇḍai Nāḍu, is a historical region located in the northernmost part of Tamil Nadu and southernmost part of Andhra Pradesh. Toṇḍaimaṇḍalam was divided into 24 kottams — smaller districts by kurumbar king and also build a royal fort (pulhal). The kottams are subdivided into smaller agricultural districts called nadus, which were groupings of several agricultural villages. At the beginning of the historical period, the kottams were mostly pastoral. The region comprises the districts which formed a part of the legendary kingdom of Athondai Chakravarti. The boundaries of Tondaimandalam are ambiguous – between the river basins of Penna River and Ponnaiyar River. During the reign of Rajaraja I, this region was called as Jayankonda Cholamandalam.