Hyderabad is the capital and largest city of the Indian state of Telangana and de jure capital of Andhra Pradesh. Occupying 625 km2 along the banks of the Musi River, located on the Deccan Plateau in the northern part of South India. At an average altitude of 542 m, much of Hyderabad is situated on hilly terrain around artificial lakes, including Hussain Sagar lake—predating the city's founding—north of the city centre. Hyderabad City has a population of about, with about in Hyderabad Metropolitan Region, making it the fourth-most populous city and sixth-most populous urban agglomeration in India. With an output of 74 billion, Hyderabad is the fifth-largest contributor to India's overall gross domestic product.