Rajarajeswaram, as the temple was named by its founder, fills a large portion of the small fort (Sivaganga Fort), encircled by moat on the east and west, the Grand Anaicut Channel (Putharu) on the south and by the Sivaganga Garden on the north. The temple entrance has an imposing gateway on the east, on either sides of which stand two small shrines dedicated to Ganapathi and Murugan and further through there is another Gopuram 90 feet high. This way leads into an outer court. A second and magnificent Gopuram further leads into the main court in which the temple is built. The inner court is about 500 feet long and 250 feet broad, is well paved with brick and stone. The court is surrounded on all sides by a cloister. The western and northern wings have Sivalingams consecrated therein and there are paintings over these walls depicting sixty-four Nayanmars, sacred sport of Siva. The outer measurement of the temple is 793 feet by 397 feet.
The main shrine of Sri Brihadisvara, the Great God - a Sanskrit rendering of the original Tamil name Peruvudaiyar- stands at the western end of the main court. It comprises of five divisions - 1. Garbhagriha or the Sanctum Sactorum and the corridor around it 2. Ardhana-Mandapam 3. Maha-Mandapam with the open aisles 4. Stapana-Mandapam with the shrine of Sri Thyagarajar 5. Narthana-Mandapam for the temple paraphernalia and where the servant waits; and 6. Vadya-Mandapam and portico for the musicians.
Main shrine has three portals named Keralantakan, Rasarasan and Thiru-Anukkan. These portals are guarded by Dwarapalikas or the guardians of the gate. They are of huge proportions and of exquisite workmanship. There are several sets like these in the temple, of which seven of them are 18 feet by 8 feet. They are all monolith, and some are of very high artistic merit, especially at the entrance of Sri Subramanya temple.
The Sivalinga of Sri Brihadisvara is probably the grandest in existence. This image was originally called Adavallan (the one who is good in Dance). Another name was Dakshina-Meru Vitanken. Both the names occur in Thiruvisaipa as the names of the deity are as same as in Chidambaram Temple. This possibly indicates that the Saiva creed derived its support at the time mainly from Chidambaram. Rajaraja Cholan calls the image Rajarajeswaramudaiyar - The Lord of Rajarajeswaram. The tower over the shrine is named Dakshina-Meru after the abode of Lord Shiva at Kailasam, the Uttara-Meru.
Sri Thyagaraja, also called Vitankar, worshiped within a portion of Stapana-Manadapam, is the patron deity of Cholas. The legend goes that their mythical progenitor Chola Muchukuntan helped Indra against the asuras, for which help, he was presented with seven images of Thyagaraja, which he installed in the seven holy places of Thiruvarur, Thiru-nagai-karonam, Thiru-kkareyil, Thirukolili, Thirumaraikadu, Thirunallaru and Thiruvamur which are known as Sapta-Vitanka-Kshetras. Rajaraja Cholan was a devout worshiper of Sri Thyagaraja at Thiruvarur where he built this great temple; and, consecrated Sri Thyagaraja at Thanjavur also, as a mark of his own piety and in commemoration of the exploits of his celebrated ancestor.
The great Vimana is of the Dravidian style of architecture. It rises to a height of about 216 feet, a tower of fourteen storeys, finely decorated with pilasters, niches and images of gods of the Hindu pantheon. The basement of the structure which supports the tower is 96 feet square. The sikhara or cupolic dome is octagonal in shape and crowns the Vimana. The gilded Kalasa or finial, over dome is 12.5 feet high. It is believed that the sikhara and the stupi does not throw on the ground. The dome rests on a single block of granite, of 25.5 feet square. Two Nandis, each measuring 6.5 feet by 5.5 feet beautify each corner of the stone which is estimated to weigh about 80 tons, and is believed to have been conveyed to the top of the tower by means of a inclined plane commencing from Sarapallam (scaffold-hollow), four miles north-east of the city.
Shrine of Sri Subramanya in the northwest corner, Shrine of Goddess Sri Brihannayagi, Sri Chandeeswara Shrine, Shrine of Ganapathy, Shrine of Nataraja in the north eastern corner, the colossal monolith figure on Nandhi, the sacred bull, in the central courtyard and the Shrine of Karuvurar.
The Chola frescos painting discovered in 1931 by Mr.S.K.Govindasamy of Annamalai University within the circumambulatory corridor Aradhana Mandapam are of great interest. These are the first Chola specimen's discovered. The passage of the corridor is dark and the enthusiast finds the walls on either side covered with two layers of paintings from floor to ceiling. Those of the upper layer are of the Nayak period, as certain labels in Telugu characters mentioned the names of Sevappa, Achyutappa and others. The Chola frescos lie underneath. An ardent spirit of saivism is expressed in the Chola frescos. They probably synchronised with the completion of the temple by Rajaraja Cholan. Saivism was at its height at that time and the Cholas were predominently of that faith.