The sacred Nilachal Hill located at a distance of 8 km west of Guwahati is believed to be an ancient 'Khasi' sacrificial site. This hill has a group of ancient temples, the most famous of which is the Kamakhya temple. The temple dedicated to the Goddess Shakti also known as Kamakshya is one of the oldest and most sacred centre for Shakti worship and Tantric Hinduism. There is a legend behind the existence of the Kamakhya temple. It is said that while Lord Shiva was carrying the corpse of his wife Sati, which was accidentally got cut into 51 pieces, her female genitalia (yoni) fell to the ground at the spot where the temple was built. At that instance the hill turned blue and came to be known as Nilachal (blue mountain).

The original 10th century Kamakhya temple was destroyed by Muslim converts but was rebuilt in 1665 by King Naranarayana of Koch Bihar. The temple complex is a nicely carved out house, made predominantly of stones. The temple consists of three major chambers. The middle chamber in the form of a cave leads to the Sanctum sanctorum that consists a natural underground spring which emanates from a fissure in a large rock. It is here the sculptured image of the Yoni of the Mother Goddess is kept. Non-Hindus are not allowed to enter the sanctum. The seven sikhara or spire in the temple is in the shape of a beehive and it has the nymph motifs and the long turtle back hall. The stone images and other relics found around the temple have been dated by archaeologists to the eighth century onwards. Kamkhya temple is famous for the ritual of animal sacrifice (specially goat) to appease the Goddess. The temple attracts pilgrims from all over India, especially during the Ambubachi Festival which usually falls in June/ July. Durga Puja and Manasa Festival are also celebrated here.

Several smaller shrines and temples dedicated to Kala Bhairava, Shiva and other Hindu deities are also located in the vicinity of Kamakhya temple. From the top of Nilachal Hill, one can get a spectacular view of the city and the Brahmaputra River.