Mazhanadu is a region between Tondai Nadu and Karnataka, formerly known as Mazhavarnadu.

In the ancient sangam age this region was ruled by Mazhavar King Kolli Mazhavan.

Famous Sangam poet Avvaiyar had cordial relations with the Mazhavar chieftains like Athiyamān Nedumān Añci of Thagadoor and Valvil Ori of Kollimalai.

Keezh-Mazhanadu was once ruled by Kolli Mazhavan and his successors, and was well-known for its water resources.

[4] The table below lists geographic and demographic parameters for districts that constitute Mazhanadu.