Hamilton (Kirikiriroa in Mori) is the centre of New Zealand's fourth largest urban area, and Hamilton City is the country's fourth largest territorial authority. Hamilton is in the Waikato Region of the North Island, approximately 130 km (80 mi) south of Auckland. It sits at a major road and rail nexus in the centre of the Waikato basin, on both banks of the Waikato River. Initially an agricultural service centre, it now has a growing and diverse economy and is the second fastest growing urban area in New Zealand. Education and research and development play an important part in Hamilton's economy, as the city is home to approximately 40,000 tertiary students and 1,000 PhD scientists. The area now covered by the city was originally the site of a handful of Mori villages (kinga), including Pukete, Miropiko and Kirikiriroa ('long stretch of gravel'), from which the city takes its Mori name.