Waikato is that region south of South Auckland and the Coromandel Peninsula, west of the southern reaches of the Coromandel Range and the Kaimai Hills, and includes the central and lower reaches of the Waikato River. There are four plains within this area: the Waikato-Waipa Basin, the Waitoa-Waihou Basin, the Hauraki Plains and the lower Waikato Plain. It is one of the most productive grass-growing regions in the world, famous for its dairy products and increasingly for its horticultural products. It benefits from a fertile combination of soil richness, rainfall and sunshine, although at one time farmers experienced major difficulties with the organic or peaty soils which have to be farmed in a careful and knowledgeable way with particular attention to drainage, fertiliser application and stocking practices. It is an intensely farmed region, with a large number of landholders owning relatively small properties compared with most other farming regions of NZ. The industrial, educational and information infrastructure that has grown around the lucrative farming business has seen Hamilton, the main town of the Waikato, grow into a busy servicing centre — from a population of less than 5,000 people in 1910, into the centre of a relatively built-up area with over 120,000 people. The Waikato is also a sheep faming area and has the largest open-cast coal mines in the country.