Te Rau Kahikatea is one of the earliest surviving houses in Gisborne and an unusual example of Carpenter Gothic architecture in the region. Erected in 1876, only six years after Gisborne was founded, the two-storey building was constructed for Archdeacon W. Leonard Williams (1829-1916), one of the pre-eminent Church Missionary Society (CMS) clergymen in the East Coast area. Located on the fringes of the colonial town, the homestead was used as a family home and for the theological instruction of Maori candidates for the Anglican clergy. Williams had been commissioned by the CMS to train indigenous students in 1850, continuing his efforts after his mission station at Waerenga a Hika near Turanga had been destroyed in the Pai Marire conflicts of 1865. Shifting his base from missionary enclaves to the new Pakeha town of Gisborne, Williams' foundation of Te Rau Kahikatea may have marked a change in the way the CMS approached the religious instruction of Maori. Indigenous faiths such as Pai Marire had caused concern among the established churches, who generally regarded such developments as 'heretical'. Training was further institutionalised when the house became the nucleus for Te Rau Theological College from 1883-1885, at which time specialised educational buildings were erected nearby. The college subsequently took Maori candidates from across the North Island, and was run by Williams until his election as Bishop of Waiapu in 1895.

The change from a Maori to a Pakeha location for theological teaching was mirrored by the striking choice of Carpenter Gothic design for the 1870s house. The elaborate bargeboards, profusion of gables and ornate verandahs of this style contrasted strongly with the simple Georgian design of Williams' previous homes. Gothic Revival architecture was closely associated with the Anglican Church in mid nineteenth-century New Zealand, and may reflect a retreat from the more egalitarian ideas of the Enlightenment, which were partly embodied in Georgian style. Asymmetrical in its layout, the interior of the building had at least four upstairs bedrooms, including one used by a maid, while the ground floor contained the Archdeacon's bedroom as well as reception and service rooms. A room with separate access off the main entrance verandah may have been used for teaching. Complemented by extensive plantings of indigenous and exotic flora in the large gardens, the house can be seen to reflect a retreat from the more direct contact with Maori culture engaged in by early missionaries in the region, including Williams himself. The house was occupied by Williams' son Herbert from 1895, when he followed his father as college principal and later as a Bishop of Waiapu. The house was employed as a vicarage from 1915, and continued to be associated with the Anglican Church until the 1990s. It was moved within the site and rotated by 90 degrees in 1976, at which time many of its lean-tos were demolished.

Te Rau Kahikatea is significant as an early building in the Gisborne region, and one that demonstrates changing relationships between Maori and Pakeha after the 1860s. It has a long and important association with the Anglican Church, being used in different capacities as Gisborne evolved from a pioneer town to a prosperous Pakeha settlement. It is significant for its association with both Leonard and Herbert Williams, who were prominent members of the Anglican clergy and members of an important missionary family. The building is a valuable example of Carpenter Gothic architecture, of additional worth for its rarity in the region. It is the only remnant of Te Rau College, which played a significant role in the religious education of Maori. Its importance is enhanced by its association with a broader historical and cultural landscape, including remnants of nineteenth-century plantings in surrounding gardens. It enjoys high public esteem for its age and aesthetic qualities, being a tangible reminder of pioneering Gisborne.