The Sanjay Gandhi Biological Park, Patna was established as a Botanical Garden vide Government of Bihar, Forest Department's letter no. 1781V dated 13.4.1970 on a chunk of 34.00 acres land being part of the Governor’s campus. His Excellency the then Governor of Bihar, Shri Nityanand Kanoongo bestowed the land to the forest department to establish the garden. The Divisional Forest Officer, Gaya Forest Division was deputed as officer-in-charge of the Garden.
Later on, in 1972 the name was changed to Biological Park by the Department of Forests, Govt. of Bihar, and, it was brought under the administrative control of the Working Plan Officer, Magadh Circle, Patna. Later on the adjoining 58.20 acres land of Revenue Department and 60.75 acres land of Public Works Department transferred to Forest Department was added to the existing Biological Park. Thus, present area of the Biological Park is approximately 153 acres. The land acquired from Public Works Department and Revenue Department is notified as Protected Forest by the State Government. The State Government has declared the park/zoo service as ‘Essential Sevice’ under the Bihar Essential Services Maintenance Act.