Katihar became a full-fledged district when it was split from Purnia in 1973. Earlier Katihar district was dominated by Choudhary Family who were the biggest landlords of Koshi zone . Founder of Choudhary family  was  Khan Bahadur  Mohammad Baksh, who holds lands of about 15,000 acres in Katihar district, 8,500 acres in Purnea.  Katihar  is  a historical place and takes  place in Indian history. It is said that Hindu Lord Shri  Krishna came here and lost mani here in Manihari (a religious place of Katihar district). Katihar was a part of Purnia district and the latter was constituted in round about 1813 along with Malda district. Under the Mughal rule, the district was constituted of Sarkar Tajpur, east of the Mahananda and Sarkar  Purnia west of the river. The province of Bihar came under Muslim rule after Bakhtiyar Khilji conquered Bihar town then capital of Bihar towards  the  close of 12th century. His successor Ghiasuddin Iwaz extended the limits of the territory to include virtually the whole of Bihar, Katihar must also have come under Mohammedan rule in the beginning of the 13th century. The district passed into the hands of the British in  1770  when Mohammad  Ali  Khan was the Governor of Purnia. Ducarrel, the first English Supervisor of Collector of the district, replaced him. In 1872 the district was transferred from the control of Bihar and Banaras Board of Commissioners to the Calcutta Board of Revenue. The early years of  British  rule  were  largely directed to establishing law and order and setting up of the revenue administration on sound footing. Anga and Magadh Kings ruled over the Katihar during the time of Mahajanpada. Raja Birat of Morang also visited the place. With the advent of Muslim rule in the North India Ikhtiyar-ud-din Bakhtiyar Khilazi subjugated this area and subsequently this area remained under indirect Mughal rule. In the English rule, Katihar  came under the rule of Zamindars, Nawab who were Indian and was helping Englishman to rule over farmers, labour classes etc. Before the partition of Bengal, Katihar was belonging to Bengal. But when the Partition divided Bengal into Bihar, Bengal and Orrisa, today’s Katihar District came under Bihar. British rule was challenged in India and Katihar was in the forefront of the agitation. With the independence of India, the people of Katihar breathed free along with all the Indians. Katihar was a sub-divisional town of Purnea district but on 2nd October 1973, Katihar acquired status of an independent district. It has a rich heritage and close linkage with the parent district of Purnia. The district derives its name after its  chief  town  of the same  name which probably got its name from a small village on the northeast called Dighi-Katihar where there is a big tank (dighi) excavated for the troops, when the soldiers of the Nawab of Purnea fought with the troops of Nawab of Murshidabad.