Sonbhadra or Sonebhadra (Hindi: सोनभद्र) is the second-largest district by area of Uttar Pradesh, India. It is the only district in India which borders four states, namely Madhya Pradesh to the west, Chhattishgarh to the south, Jharkhand in the south-east and Bihar to the north-east. 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 south-east of the state, and is bounded by Mirzapur District to the northwest, Chandauli District to the north, Kaimur and Rohtas districts of Bihar state to the north-east, Garhwa district of Jharkhand state to the east, Balrampur District 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 much bauxite, limestone, coal, gold, etc. It is called the "Energy Capital of India" because there are so many power plants.