The taluk, which has its headquarters in its namesake town of Thiruvennainallur, was created in 2019 as part of the bifurcation of Viluppuram district.

[2] Thiruvennainallur taluk covers an area of 248 square kilometres (96 sq mi) in the southwestern part of Viluppuram district.

The Thenpennai River runs through the taluk, and defines parts of its northern border.

[3][4] As of 2019, Thiruvennainallur taluk had a population of 151,027 people living in an area of 234 square kilometres (90 sq mi),[2] resulting in a population density of 645.4/km2 (1,672/sq mi).

The largest settlements in the taluk are the headquarters of Thiruvennainallur, and the villages of Sithalingamadam and Anathur.