[3] Its capital was Sonepur, the only significant town in the area.

The former state's territory is in the present-day Subarnapur district, Western Odisha.

The Sonepur state was founded in 1650 when the fourth Chauhan ruler of Sambalpur Madhukar Dev, conquered the region from the Bhanja rulers of Boudh and entrusted it to his younger son Madan Gopal who hence became the founder of the Chauhan dynasty branch of Sonepur.

[4][5] The state came under the control of the British Empire post the Maratha defeat and later king Niladhar Singh Deo was awarded titles for services rendered to the British during the Sambalpur uprising.

[6] After Indian independence, Sonepur's last ruler acceded to the newly independent Dominion of India, on 1 January 1948 with the state forming much of the present-day Subarnapur district.