This area of New Zealand is generally known as "King Country".  It's not a 'governmental' district, but includes parts of  The Waikato, and Manawatu-Wanganui/Whanganui.  (notable distinction being discussed while I was there.)   When the Treaty of Waitangi was signed in 1840, several copies in the Maori language were sent out for signature by the Maori chiefs of both islands.  At that time,  Potatau Te Wherowhero ruled The Waikato.  He had this to say to the British who appeared with a piece of paper for him to sign.   Prescient on his part, as territories controlled by Treaty signatories were quickly overrun by British settlers in questionable land grabs.   By 1845, large portions of New Zealand had erupted in the New Zealand Wars / Maori Wars / Land Wars, which continued for thirty years.    Many of the battles occurred in this district.  The  'King Country' appellation is in reference to the Maori Chiefs who united under Te Wherowhero's son, King Tawhiao in resistance to the British claims of sovereignty.