Gaya is one of the thirty-eight districts of Bihar state, India. It was officially established on 3 October 1865. The district has a common boundary with the state of Jharkhand to the south. Gaya city is both the district headquarters and the second-largest city in Bihar.

Gaya finds mention in the great epics, Ramayana and Mahabharata. Rama along with Sita and Lakshmana visited Gaya for offering PIND-DAAN to their father Dasharath. In Mahabharata, the place has been identified as Gayapuri. About the origin of the name ‘Gaya’ as referred to in Vayu Purana is that Gaya was the name of a demon (Asura) whose body was pious after he performed rigid penance and secured blessings from Vishnu. It was said that the Gayasura’s body would continue to be known as Gaya Kshetra.

Gaya district occupies an area of 4,976 square kilometres (1,921 sq mi), comparatively equivalent to the island of Trinidad.

In 2006 the Ministry of Panchayati Raj named Gaya one of the country’s 250 most backward districts (out of a total of 640).It is one of the 36 districts in Bihar currently receiving funds from the Backward Regions Grant Fund Programme (BRGF).

In 1976 Gaya district became home to the Gautam Budha Wildlife Sanctuary, which has an area of 260 km2 (100.4 sq mi).

According to the 2011 census Gaya district has a population of 4,379,383, roughly equal to the nation of Moldova or the US state of Kentucky.This gives it a ranking of 42nd in India (out of a total of 640).The district has a population density of 880 inhabitants per square kilometre (2,300/sq mi).Its population growth rate over the decade 2001-2011 was 26.08%.Gaya has a sex ratio of 932 females for every 1000 males, and a literacy rate of 66.35%.