Rarh region is a toponym for an area in the Indian subcontinent that lies between the Chota Nagpur Plateau on the West and the Ganges Delta on the East. Although the boundaries of the region have been defined differently according to various sources throughout history, it is mainly coextensive with the state of West Bengal, also comprising parts of the state of Jharkhand in India.

West Bengal is a state in the eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabitants within an area of 88,752 km2 (34,267 sq mi) as of 2011. The population estimate as of 2023 is 102,552,787. West Bengal is the fourth-most populous and thirteenth-largest state by area in India, as well as the eighth-most populous country subdivision of the world. As a part of the Bengal region of the Indian subcontinent, it borders Bangladesh in the east, and Nepal and Bhutan in the north. It also borders the Indian states of Jharkhand, Odisha, Bihar, Sikkim and Assam. The state capital is Kolkata, the third-largest metropolis, and seventh largest city by population in India. West Bengal includes the Darjeeling Himalayan hill region, the Ganges delta, the Rarh region, the coastal Sundarbans and the Bay of Bengal. The state's main ethnic group are the Bengalis, with the Bengali Hindus forming the demographic majority.