Mahendragarh district is one of the 21 districts of Haryana state in northern India. The district occupies an area of 1,859 km². The district has a population of 812,022 (2001 census). Narnaul city is the administrative headquarters of the district. Mahendragarh is one of the very few districts in India where the name of the district and its main town are different. Ateli and narnaul have a Sonalika Tractors agency named as Piyush Tractors.

The district is named after Mahendragarh town, which was previously known as Kanaud. The previous name was derived from the Kanaudia group of Brahmins. It was founded by Malik Mahdud Khan, a servant of Babur.

Mahendragarh district was formed in 1948 by grouping different tracts of erstwhile princely states; Narnaul and Mahendragarh tehsils from Patiala State, Dadri (Charkhi Dadri) from Jind State and a part of Bawal nizamat from Nabha State. It became a part of Patiala and East Punjab States Union (PEPSU) state. On November 1, 1956, with the merger of PEPSU with Punjab, it became a part of Punjab state and with the formation of Haryana state in 1966, it became a part of the newly formed state. Rewari tehsil of Gurgaon district was added to it in 1972 but Rewari tehsil was made a separate district in 1989.

The district lies between north latitude 270 47 to 280 26 and east longitude 750 56’ to 760 51’. It is bounded on the north by Bhiwani and Rewari districts, on the east by Rewari district and Alwar district of Rajasthan, on the south by Alwar, Jaipur and Sikar districts of Rajasthan, and on the west by Sikar and Jhunjhunu districts of Rajasthan.

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

Dhosi Hill is an important tourist site in the District. Known as Chyawan Rishi Ashram it is a Vedic period site. It is here that Chyawanprash was formulated for the first time.

According to the 2011 census Mahendragarh district has a population of 921,680,roughly equal to the nation of Fiji or the US state of Delaware.This gives it a ranking of 462nd in India (out of a total of 640).The district has a population density of 485 inhabitants per square kilometre (1,260/sq mi). Its population growth rate over the decade 2001-2011 was 13.43%.Mahendragarh has a sex ratio of 778 females for every 1000 males, and a literacy rate of 78.9%.