The archaeological remains of ancient Pataliputra namely the Eighty pillared hall and Arogya Vihar are located at Kumrahar about six kms east of Patna railway station.

Ancient literature refers Pataliputra by various names like Pataligrama, Patalipura, Kusumapura, Pushpapura or Kusumdhvaj. In 6th Century B.C. it was a small village where Buddha, sometime before his mahaparinirvana, had noticed a fort being constructed under the orders of King Ajatasatru of Rajagrih for defence of Magadh kingdom against the Lichchavi republic of Vaisali. Impressed by its strategic location king Udayin, son and successor of Ajatasatru, shifted the capital of Magadh from Rajgrih to Pataliputra in the middle of 5th Century B.C. For about next thousand years Pataliputra remained the capital of great Indian empires of Saisunaga, Nanda, Maurya, Sunga and Gupta dynasties. The place has also been an important centre of activity in the fields of education, commerce, art and religion. During Asoka's time the third Buddhist council was held here. Likewise Sthulabhadra, the eminent Jain ascetic had convened a council here during the time of Chandragupta Maurya.

The first vivid account of Pataliputra including its municipal administration comes at about 300 B.C. from Megasthenese, the celebrated Greek ambassador at the court of Chandragupta Maurya, who mentions it as Palibothra in his book named Indica. According to his account the spread of the city was like a parallelogram, about 14 kms east-west along the river Ganges and 3 kms north-south. The circumference of the city was about 36 kms. The city was protected by massive timber palisades and further defended by a broad and deep moat which also served as a sewer of the city. Kautilya also in his book Arthasastra indicates wide rampart around the city. Remnants of the wooden palisades have been discovered during a series of excavations at Lohanipur, Bahadurpur, Sandalpur, Bulandibagh, Kumrahar and some other locations in Patna.

The Mauryan pillared hall at Kumrahar was brought to light by excavations conducted by Archaeological Survey of India in the years 1912-15 under D.B. Spooner with the funds donated by Sir Ratan Tata. In this excavation traces of 72 pillars were found. Further excavations in 1951-55 by K.P. Jayaswal research Institute, Patna exposed 8 more pillars of the hall and four additional ones belonging to the entrance or porch. Since then it is popularly refered as the 'Eighty Pillared Hall'.

All the pillars were made of black spotted buff sandstone monoliths with a lustrous shine typical of the Mauryan period.

Regarding the nature of this hall, it has been variously assigned as the palace of Asoka, audience hall, throne room of Mauryas, a pleasure hall or the conference hall for the third Buddhist council held at Pataliputra in 3rd Century B.C. during the reign of Asoka.

Excavations by K.P. Jayaswal research Institute have unearthed brick structures of Gupta period identified as Arogya Vihara or hospital-cum-monastery on the basis of an inscribed terracotta sealing discovered from the place which bears the inscription reading 'Sri Arogya Vihare Bhikshusanghasya'. Another small red potsherd was also found inscribed with the word 'Dhanvantareh', possibly referring to the name or the title of the presiding physician of Arogya Vihar. Hence it can be surmised that this hospital was run by Dhanvantari, the famous physician of Gupta period.

Important finds from the excavation of this area include copper coins, ornaments, antimony rods, beads of terracotta and stone, dices of terracotta and ivory, terracotta seals and sealings, toy carts, skin rubbers, terracotta figurines of human, bird and animals and some earthen utensils. An exhibition hall at the site depicts the story of Kumrahar through antiquities, photographs, translites, diorama and other illustrations for the convenience of visitors.