Who among the following is known as the land of red river and blue hills?

The correct answer is Assam. Key Points Assam is known as the land of the Red River and Blue Hills. Assam is referred so as the Red River refers to the river Brahmaputra, and the blue hills refer to the hills that shine at a distance forming a blue cloud. Additional Information Assam is a state in Northeast India, situated south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of 78,438 km² (30,285 sq mi). According to Area, the Indian State Assam ranked 16th in India. Guwahati is the largest metropolitan area and urban conglomeration in Assam, administered under the highest form of the local urban body-Guwahati Municipal Corporation. The state is bounded to the north by Bhutan and Arunachal Pradesh ; to the east by Nagaland and Manipur ; to the south by Meghalaya , Tripura , Mizoram , and Bangladesh ; and to the west by the Siliguri Corridor by West Bengal .