Tūrangawaewae House was erected in 1917-1919 as a kauhanganui, or parliament building, for the Māori King movement. It represents an important assertion of Māori identity and resistance to Pākehā-dominated political structures in the early twentieth century. The Kīngitanga, or King movement, had been founded in the 1850s to counter the growing spread of colonial settlement in the Waikato and beyond. It consisted of a broad federation of tribes, including many descended from the Tainui canoe. Forced to move from its base at Ngāruawāhia after the third New Zealand - or Waikato - War (1863-1864), the movement set up a parliament in 1891 in response to the under-representation of Māori in the country's electoral system. Initially meeting away from the main centres of Pākehā settlement, the parliament marked a return to its original heartland by constructing a new assembly house at Tūrangawaewae in Ngāruawāhia. The building was erected in the centre of what had become an established colonial town, in an area of symbolic and spiritual importance for Kīngitanga. In particular, it lay within the site of the papakāinga where kingship had been invested in Pōtatau Te Wherowhero (?-1860) and his son Tāwhiao (?-1894), who were the earliest leaders of the movement. It was also located close to Pōtatau Te Wherowhero's initial place of burial, and the site of an earlier assembly building abandoned in 1864.

The purpose-built structure was of grand construction, affirming the movement's mana through its appearance as well as location. Designed by the Hamilton-based firm of Warren and Blechynden, the structure combines Māori and Pākehā forms in an unusual fusion of cultural traditions. The concrete and stucco building includes a symmetrical façade, with dormer windows in its taller central element and single-storey wings on either side. Its general Arts and Crafts style can be seen to acknowledge the European origins of the parliamentary idea as well as the residential nature of its immediate Pākehā neighbourhood. Māori identity is asserted through prominent carvings by Te Motu Heta on its porch and gables, while its interior includes a painted assembly hall once known as the 'throne room', whose raised dais was draped with feathers and flax for a royal chair. The building was opened in the presence of tribal representatives from throughout the Auckland province in March 1919 but was rarely, if ever, used for parliamentary gatherings as disenchantment with progress on political representation grew. In 1920, it housed meetings that planned the foundation of a more traditional group of buildings at nearby Tūrangawaewae Marae, which took over as a focus of political and social activity. Empty for long periods of time, the building was employed as a pioneering health clinic in the 1940s and by the Māori Land Court in ensuing decades. The Tainui Māori Trust Board occasionally met there after being set up in 1946 to deal with compensation for tribal land confiscated after the third New Zealand War. The building's mana and purpose were restored following refurbishment in the 1980s, when it became the first permanent home of the board.

Tūrangawaewae House is nationally significant for its associations with the King movement, and the development of Māori protest at New Zealand's political system. It is important as one of the earliest surviving Kīngitanga buildings in its Waikato heartland, with strong connections to prominent Māori leaders such as King Tāwhiao, King Te Rata (?-1933) and Princess Te Puea (1883-1952). The building is architecturally valuable for its unique fusion of Arts and Crafts and traditional Māori styles, and for being one of the earliest official Māori structures designed by an architectural firm. It contains important carvings and painted interior details, including a unique pattern designed for King Tāwhiao in 1870. The building is unusual as a major historic Māori structure in an urban setting, and may be considered a precedent for the modern urban marae. It is an important reminder of the long association Māori have had with Ngāruawāhia, and significant for its association with health and land rights as well as ongoing Tainui cultural and political affairs. A striking component of the local streetscape, the building has additional value for its proximity to other historic structures and places of cultural significance. These include the Waipa and Waikato rivers, which are of great spiritual importance to Tainui, and a monument marking the original burial place of Te Wherowhero.