The district derives its name from the headquarters town Fatehabad. The town was founded by Firoz Shah Tughlak in the 14th century. He named it after his son Fateh Khan, as Fatehabad. The Fatehabad district was carved out of Hisar district on 15-07-1997.
Aryans at first on the banks of the rivers -the Saraswati and the Drishadvati, and in the course of their expansion covered a wider area of Hissar and Fatehabad. The area was probably included in the kingdom of Pandavas and their successors. Panini mentions quite a few towns of the region-Aisukari, Taushayana (Tohana) and Rori which have been identified with Hissar, Tohana and Rori, respectively. According to Puranas, the areas of Fatehabad district remained a part of Nanda empire. The discovery of Ashokan pillars at Hissar and Fatehabad shows that the area of the district remained a part of Mauryan empire. The people of Agroha area assisted Chandra Gupta Maurya in the war against Greeks.
After the fall of the Mauryas and Sungas, the Agras along with the Yaudheys-the republican tribes of the region-asserted for their independence. The Agras settled in the region covering Agroha and Barwala. They issued coins from Agroha, the capital headquarters. As attested by the discovery of coin-moulds and terracottas, the region was a part of Kushan empire. According to A.S. Altekar, the Yaudheys made a second bid for independence towards the end of the second century A.D., came out successful in their venture and succeeded in freeing their home-land and ousting Kushans.
This finds support from the Agroha seal1. The early 11th century saw the Ghaznavid inroads in this area. Sultan Masud led the expeditions towards Agroha. The Chauhans seem to have taken special measures for protecting the area against Muslim incursions. The area of Agroha passed on to the Muslim rule after the defeat of Prithvi Raj III in the Second Battle of Tarain (1192).
After the Battle of Tarain, Sultan Shihab-ud-din Muhammad Ghuri placed one of his ablest generals in the Indian campaigns. But it appears that any meaningful control could not be established. Seizing the opportunity, a Rajput clan, Jatus, a branch of Tomar/ Tanwar Rajputs, widely extended their power in Fatehabad area including Agroha. Firuz (1351-88) shot these areas into prominence. The ruler came to have somewhat unusual fancy for the tract (Hissar). It is a great credit to him that he established new towns of Fatehabad and Hissar and built two canals; one taking off from Ghaggar at Phulad and following the course of Joiya up to the town of Fatehabad. After the death of Firuz (1388), chaos and confusion spread all round. The situation deteriorated still further when Timur invaded in 1398. During his marching, Timur invested Fatehabad which was captured without any opposition from the inhabitants. Lastly, the invader reached Tohana but he could not set- up his permanent rule over the area. He soon left for Samana after looting these areas. The areas of Fatehabad came under the control of Mughals-Babar and Humanyun.
There is a small and beautiful mosque known as Humanyun mosque at Fatehabad. The legend assigns the association of the mosque to the Mughal Emperor Humanyun who in his flight after his defeat at the hands of Sher Shah Suri happened to pass through Fatehabad. Fatehabad was one of important Mahals during Akbar's timeBy 1760, the areas became the scene of a sort of triangular duel between the sturdy Sikhs of north-east, marauding Bhattis of north-west and the Muslim chiefs of the south. None of them could, however, hold the region permanently except for the Bhattis who became the masters of Fatehabad pargana. In 1774, Maharaja Amar Singh of Patiala along with his famous minister Dewan Nanumal laid seize to the stronghold of Bighar near Fatehabad which fell shortly afterwards.
The Raja then took Fatehabad and Sirsa and invested Rania held by Bhattis. Tohana also was seized by the Chief of Patiala. But after a treaty of Jind in 1781, Fatehabad and Sirsa were made over to the Bhattis and remaining territories were allowed to be retained by the Sikhs. By 1798, Agroha and Tohana were important parganas under the control of George Thomas. When George Thomas was driven out from here by the Sikh-Maratha-French Confederacy, a French Officer Lt. Bourquian controlled these areas on behalf of Marathas. He is said to have rebuilt the towns of Tohana and Hissar. Later these areas were placed under the charge of Illias Beg, a Mughal noble of Hansi. With the treaty of Surji Anjangaon 1803, the British became the rulers of this area and Marathas were vanquished forever.
In November, 1884, the Sirsa district was abolished and Sirsa tahsil after the distribution of villages was formed. In 1889, 15 villages forming a detached block known as Budhlada were transferred form Kaithal tahsil to Fatehabad tahsil. The Barwala tahsil containing villages was abolished with effect from January 1, 1891 and its area was distributed between 3 contiguous tahsils; 13 villages going to Hansi, 24 to Hissar and 102 to Fatehabad. At the same time 13 villages were transferred from Hissar tahsil to Bhiwani tahsil and a sub-tahsil was established at Tohana in Fatehabad tahsil. In 1923, the Tohana sub-tahsil was transferred from Fatehabad to Hissar tahsil. In 1972, Tohana sub-tahsil was upgraded to tahsil. Two sub-tahsils, one at Ratia of tahsil of Fatehabad and other at Adampur of Hissar tahsil were created in 1979. By the end of 1978, the Hissar district comprised 486 villages, divided between tahsils of Fatehabad -166; Hissar-115, Hansi-119 and Tohana-86. Fatehabad came into existence as a full-fledged district with effect from 15-7-1997, now having three sub-divisions, three tahsils and three sub-tahsils.