Penna is a river of southern India. This is a unique river in world where 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 km2: 6,937 km2 in Karnataka and 48,276 km2 in Andhra Pradesh. Along with this main stream there is another stream south towards Tamilnadu 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 is an ancient hill station built by Ganga Dynasty in the Chikkaballapur district of Karnataka state. It is 10 km from Chickballapur town and approximately 60 km from Bengaluru. The hills are near the town 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 first ever SAARC summit hosted by India was held at Nandi Hills in 1986.