It is irrigated by an elaborate system of dams, cuts and canals in connexion with the rivers Cauvery and Coleroon, and the soil is exceedingly productive.
The principal rivers are the Cauvery, Bhavani, Noyil, and Amravati.
The delta of the Cauvery occupies the flat northern part, which is highly cultivated, dotted over with groves of coconut trees, and is one of the most densely populated tracts in India.
In the north is a range of primitive trap-hills known as the Cauvery chain, extending eastwards from the Nilgiris, and rising in places to a height of 4000 ft.
Here is supposed to have been the northern frontier of the ancient Chola kingdom, the successive capitals of which were Uriyur on the Cauvery, Combaconum and Tanjore.