Near 35 Km away from Thiruvannamalai on the east is a fort once ruled by Raja Desingh and his successors, and now in its irrecoverable ruins. It was a fortified strong hold built around the hills and on their tops in Gingee in 1200 AD, ruled by different Indian kings, later it fell and foreigners captured. The  remains of the fort are left as monuments which decidedly depict and different cultures and civilization that existed these days. The fort which is in its ruins tell us that all men made things would wear away with time and perish without leaving away sign or trace. Only one is permanent. - God.

History says that, Fort was fortified around 1200A.D. by Anandakone, chief of local shepherd community. The 800 years old fort have changed to many hands before it was annexed to the Vijayanager Empire. in 1240 AD, Krishnakone successor of Anandakone fortified the Northern hill and later it is called as Krishnagiri.

Senji Fort was in the hands of Kones, Kurumbars, Chola, Nayaks, Maraths, Mughals, Nawabs, French and British chronically. Aurangazeb captured Senji in 1691 AD and appointed Sarup Singh as chief but under the control of Nawab of Arcot. The most famous young and courage king who ruled here was Raja Desingh and he is the son of Sarup Singh. Now the entire fort is maintained by archaeological department.

On the left side of the road there is a hill known as Rajagiri. This is originally known as Anandhagiri and the Maharatha King Chathrapathy Sivaji renovated this fort and strength in 17th century and renamed it as Rajagiri.

This fort at the height of 968 ft from sea level, 800ft from the base. In the base of Rajagiri hill the known structures are Kalyana Mahal, Horses Table, Granite Grading Stone Elephant Baths, Wrestling Arena, Explosives Storing Room, Granary, Prayer Hall, Chetti Tank, and Chakkari Tank and Anchaneya temple.

At the top of the hill there are mint, a temple without idol, Durbar, and clock tower, a canon of old time. On the way to Rajagiri the place visible to our eyes are Bala Aranganatha Temple, Choultry Tank, Kuvala kanni amman shrine.

On the right side of the road as well as south to Rajagiri, there is an another famous hill known as Chandragiri. Chandragiri is also known as Chkkili malai, Changili malai. On the top of hill there is a Mahal, a tank, Granary and Ranganadar temple.

It is located to the north of Rajagiri. The audience hall on this hill can be climbed in a flight of steps. With in the audience hall there are two stone-built Granaries, a pillared hall, two temples and an audience chamber. And also Sipoys Mandapa and Bhadrakali temple are on Krishnagiri Fort.