Two princely State of Gangapur and Bonai constitute the present district of Sundargarh, consequent upon merger of the princely States in 1948. It is understood that the district comprised in ancient time, the territory of South Kosala. These states were once under the suzerainty of Sambalpur, which formed part of the dominion of the Maratha Rajas of Nagpur. The Maratha chief Raghuji Bhonsle under the treaty of Deogaon, ceded them to the British Government in 1803. But they were restored to him by special engagement in 1806. They were finally ceded in 1826. In 1905, they were transferred from the control of the commissioner of Chhotanagur to that of Orissa.