Hisar district is one of the 21 districts of Haryana state, India. Hisar city serves as the district headquarters. The district is also part of Hisar division, which is headed by a commissioner who is employed by the Indian Administrative Service.

The largest district in Haryana until its 1966 reorganization, some parts of Hisar were transferred to the newly created Jind district. In 1974, Tehsil Bhiwani and Loharu were transferred to Bhiwani district. Hisar was further bifurcated when Sirsa district was formed. Fatehabad district was later created as well.

Hisar is a divisional headquarters of the Hisar division Divisional Commissioner and also the headquarters of Police Range. It is also a battalion headquarters of B.S.F. 3rd Bn. H.A.P. and commando force. In order to accommodate all of these departments, a five storey District Administrative Complex was built, with the offices transferred in 1980. It adjoins the new Judiciary Complex, which is also made functional. This administrative and judiciary complex is the largest in Haryana; as a district headquarters it may be one of the largest in the country.

It is one of the five cities belonging to Indus Valley Civilization while its name is cited in the history books in the context of Indus civilization and in general knowledge books as the location of Banawali, one of five sheep farms. As of 2011 it is the second most populous of the 21 districts of Haryana, after Faridabad.

Hisar is also known as the steel city because of the Jindal Stainless Steel Factories. It also the largest producer of galvanized iron in India.

the 2011 census the district had a population of 1,742,815, roughly equal to the nation of The Gambia or the US state of Nebraska.This gave it a ranking of 276th in India out of a total of 640 districts.The district has a population density of 438 inhabitants per square kilometre (1,130/sq mi).Its population growth rate over the decade 2001-2011 was 13.38%.Hisar has a sex ratio of 871 females for every 1000 males, and a literacy rate of 73.2%.Haryanvi is the most spoken dialect in the district. Hisar is 98% Hindu, only about 40,000 are Muslims, rest are mostly Jain and Sikhs.

Over the past three centuries Hisar had been the birthplace of individuals including Sardar Ishri Singh, Sardar Harji Ram and Rai Bahadur Sardar Nau Nihal Singh who were honorary magistrates in pre-Independence Hisar. Noteworthy individuals include the Captain Abhimanyu Sindhu – BJP national spokesperson and Minister in Haryana from Narnaul, late Dr. Gopi Chand Bhargava – the First Chief Minister of Punjab, Om Prakash Jindal – former chairperson of Jindal Industries and his wife Savitri Jindal, Subhash Chandra – the Chairman of Essel Group (Zee Network), Yash Tonk – a Bollywood actor, Manish Joshi Bismil – The theatre director, General Vijay Kumar Singh-Former Army Chief, General Dalbir Singh-Army Chief.