Sonbhadra or Sonebhadra is the 2nd largest district of Uttar Pradesh, India.Sonbhadra is the only district in India which borders four states namely Madhya Pradesh, Chhattishgarh Jharkhand and Bihar.The district has an area of 6788 km² and a population of 1,862,559 (2011 census), with a population density of 270 persons per km².It lies in the extreme southeast of the state, and is bounded by Mirzapur District to the northwest, Chandoli District to the north, Kaimur and Rohtas districts of Bihar state to the northeast, Garhwa district of Jharkhand state to the east, Koriya and Surguja districts of Chhattisgarh state to the south, and Singrauli district of Madhya Pradesh state to the west. The district headquarters is in the town of Robertsganj.Sonbhadra district is an industrial zone and it has lots of minerals like bauxite, limestone, coal,gold etc.Sonbhadra is called as Energy Capital of India because there are so many power plants.

Sonbhadra lies between vindhya and Kaimur hills.So it is hilly region with natural beauty due to which First Prime minister of India Pt. Jawahar Lal Nehru called sonbhadra The Switzerland of India.

Based on evidence from religious and cultural perspectives Ramayana and the Mahabharat, Huyen found here is the cultural symbol. By Jarasandh many rulers in the Mahabharat war was maintained prisoner here. In the third century, this was the capital of the kings of Kantipuri wakatak Nagvanshi dynasty till ninth centuries it was dominated. Abhor dynasty kings and powerful kings of kol were also ruled in this area.

The Sone River flows through the district from west to east and its tributary the Rihand River, which rises to the south in the highlands of Surguja district of Chhattisgarh, flows north to join the Son in the center of the district. Sonbhadra is located in the south-eastern ranges of the Vindhyachal mountain. The Govind Ballabh Pant Sagar, a reservoir on the Rihand, lies partly in the district and partly in Madhya Pradesh. The district has historic, cultural, and ecological affinities with the Bagelkhand region. Robertsganj is the district headquarters, but Obra and Renukoot are the bigger and developed cities. Almost 80 km from Varanasi, the cultural centre of Indian epitome of Vedic civilisation, holds a prime importance as the district headquarters.

Sonbhadra has a relatively subtropical climate with high variation between summer and winter temperatures. The average temperature is 30 °C–42 °C in the summer and 2 °C–15 °C in the winter. The weather is pleasant in rainy season from July to October.

According to the 2011 census Sonbhadra district has a population of 1,862,559, of which male and female were 971,344 and 891,215 respectively. roughly equal to the nation of Kosovo or the US state of West Virginia.This gives it a ranking of 254th in India (out of a total of 640).The district has a population density of 270 inhabitants per square kilometre (700/sq mi).Its population growth rate over the decade 2001-2011 was 27.27%.There are 22.6% people belong to scheduled cast and 20.7% people belong to scheduled tribes.

Sonbhadra has a sex ratio of 918 females for every 1000 males. In census enumeration, data regarding child under 0-6 age were also collected for districts Sonbhadra. There were total 323,092 children under age of 0-6 against 302,834 of 2001 census. Of total 323,092 male and female were 167,870 and 155,222 respectively. Child Sex Ratio as per census 2011 was 925 compared to 956 of census 2001. In 2011, Children under 0-6 formed 17.35 percent of Sonbhadra District compared to 20.69 percent of 2001. There was net change of -3.34 percent in this compared to previous census.