Barmer District is a district in Rajasthan state of India. It is located in the western part of Rajasthan state forming a part of the Thar Desert.Barmer is the third largest district by area in Rajasthan and fifth largest district in India.District headquarters is in the town of Barmer. The other major towns in the district are: Balotra, Guda Malani, Baytoo, Siwana, Jasol and Chohatan. Recently, a large onshore oil field has been discovered and made functional in Barmer district.

In earlier times, the district was known by the name Mallinath. Mallinath was the son of Rao Salkha and Mallinath is a God who is still worshiped by Rajputs. The whole area around the river Luni was said to have Malani, derived from the name Mallinath. In the 18th century the name Barmer or Balmer was adopted by the British rulers of India and is derived from the name of the earlier 13th century ruler Bahada Rao Parmar (Panwar) or Bar Rao Parmar (Panwar), it was named Bahadamer (“The Hill Fort of Bahada”).

Barmer is located in the western part of the state forming a part of the Thar Desert. The district borders Jaisalmer district in the north, Jalore district in the south, Pali district and Jodhpur district in the east, and Pakistan in the west.

The total area of the district is 28,387 square kilometres (10,960 sq mi).After Jaisalmer district and Bikaner district, it is the third largest district of Rajasthan. It is also the fifth largest district in the country.

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

Barmer district is part of the Great Indian Desert or Thar Desert. Like all other districts in the desert region, Barmer is known for its folk music and dance. The Bhopas (priest singers) are found in Barmer, who compose music in honour of the deities of the region and its war heroes. The other folk musicians come from a community called the Muslim Dholis (drummers) for most of whom this is the only means of livelihood. Langas and Manganiars are the some of these communities.

Siwana fort, in Siwana Tehsil, is a very old fort, estimated at over a thousand years old. In local language its name is Gadh Siwana.. Jogmaya Gadh Mandir, in Barmer is a very old temple of Devi Jogmaya and is popular temple specially for Navratri. Sujeshwar Hanuman Tekri, Shiv Mandir, Jasedar Dham, Indroi Temple, Safed Aakda, Nakodaji, Juna Keeradu, Barmer Desert, Nimbdi are some other attractions in Barmer City.

In 2009, the Barmer district came in news due to its large Oil basin. The British exploration company Cairn Energy is going to start the production soon in the year 2009 on the large scale. Mangala, Bhagyam and Aishwariya are the major oil fields in the district. This is India’s biggest oil discovery in 22 years. Cairn works in partnership with state owned Oil and Natural Gas Corporation (ONGC).Cairn holds 70% in the field, while state-run ONGC holds the remaining 30%. In March 2010, Cairn increased oil potential from this field to 6.5 billion barrels of oil – from an earlier estimate of 4 billion barrels.