On the mainland, the region extends from the mouth of the Kaipara Harbour in the north across the southern stretches of the Northland Peninsula, past the Waitākere Ranges and the isthmus of Auckland and across the low-lying land surrounding the Manukau Harbour. The region ends within a few kilometres of the mouth of the Waikato River. It is bordered in the north by the Northland Region, and in the south by the Waikato region. It also includes the islands of the Hauraki Gulf.