Theni Allinagaram is a valley town and a municipality, situated in the Indian state of Tamil Nadu at the foothills of Western Ghats.

[2] According to 2011 census, Theni Allinagaram had a population of 94,453 with a sex-ratio of 999 females for every 1,000 males, much above the national average of 929.

[2] As per the religious census of 2011, Theni Allinagaram had 95.04% Hindus, 3.18% Muslims, 1.63% Christians, 0.02% Sikhs, 0.01% Buddhists, 0.12% following other religions and 0.01% following no religion or did not indicate any religious preference.

[5] Theni houses the office of the (revenue) District Collector.

Periyakulam has the district court, which was built and operated in the British period.