Rising abruptly from the plains to a height of 83 metres is Rock fort, the famous land mark of Tiruchirapalli. Tiruchirapalli's historic associations stretch from Chola times to the 18th century Karnatak wars, when Britain and France espoused the cause of rival princes. Four hundred and thirty-four steps down into the rockside and interspersed with shrines and landings lead the pilgrim to an ancient temple dedicated to Ganapati. A tank and a pavilion at the foot of the Rock fort is the scene of the temple's float festival.

Vellore is one of the finest examples of military architecture in South India. It is a perfect specimen of a jala durg, water fort. Vellore was built towards the end of the 14th century by the Hindu Vijaynagar kings and held by them until their defeat in 1565. A self-styled Raja of Vellore had, on the fall of Vijaynagar, taken control of what had become an important provincial capital. In 1677, when Shivaji, the great Maratha chieftain, began his campaign in the Deccan to gain a foothold in the Karnatic, he did so by investing Vellore. The most impressive building within the fort is the Jalakantesvara Temple, dedicated to Shiva, remarkably it was almost undamaged during the Muslim tenure of Vellore. The British built a bridge over the moat and most of the buildings now in use within the fort walls.