The timber library and mission house at The Elms in Tauranga are the oldest known surviving buildings in the Bay of Plenty region. They are remnants of the Church Missionary Society (CMS) settlement at Te Papa mission, which had been founded in 1835. The mission was located on a peninsula between the Ngaiterangi pa settlements at Otumoetai and Maungatapu, and was part of a southward expansion of CMS operations from their earlier base in the Bay of Islands. It became the major station in the area from early 1838, ministering to Maori settlements and other CMS stations in the surrounding regions including Thames and Rotorua. With a growing sense of permanence, raupo buildings in the settlement began to be replaced with timber structures during the same year, including the mission house and library. These marked an important stage in the development of the mission, asserting an identity that contrasted more strongly with its surrounding Maori environment.

The library is the earliest of these timber buildings to survive at Te Papa, having been constructed in 1838-1839. It was erected to house books and religious papers, reflecting the importance of education to the CMS mission. The single-storey building is of simple Georgian style with a central door and flanking windows. It is small and square in plan, originally with a small basement, while a chimney was added in 1844 to prevent damp. Construction of the one and a half-storey mission house was started in 1838 to a similar Georgian design. Built to house the missionary Alfred Brown (1803-1884) and his family, it was not finished until 1847, after Brown had been raised to the position of archdeacon. The dwelling is arranged with several large rooms downstairs, with shuttered French windows looking out onto a garden planted with imported species, including Norfolk Island pines and an English oak. The building is closely associated with later events in the third New Zealand - or Waikato - War (1863-1864). Fighting between Maori and British troops occurred at the Battle of Gate Pa immediately to the south of the mission land, and a peace was concluded in front of the house. After the government obtained most mission land for a military settlement, now modern Tauranga, the dwelling and its grounds were purchased by Brown and his second wife Christina (nee Johnston, c.1818-1887) in 1873, and run as a small estate re-named The Elms. Little altered in their basic form, the house and library belonged to the same family until 1998 and continue to be surrounded by extensive gardens and other remnants of the mission complex and estate, now part of The Elms Historic Area.

The mission house and library are nationally significant for reflecting early contact between the CMS and Maori in the Bay of Plenty region. They are important for their association with the spread of Christianity in the Bay of Plenty and beyond. The library is particularly valuable as the earliest surviving purpose-built structure of its type in the country, while both the library and house are among a very small group of New Zealand buildings built or started in the 1830s. They are also among the best-preserved early structures in the country, and are important for our understanding of construction techniques and design in the early colonial period. They similarly provide valuable information on attitudes towards religion, education and domestic life, including those involving gender, race and class. The buildings are extremely valuable for the extensive survival of their original interiors and fixtures, while also retaining numerous chattels such as original books. They have important connections with the third New Zealand War, and prominent colonial personalities such as Alfred and Charlotte (1795/96?-1855) Brown. The buildings are significant as the major surviving buildings in an extensive cultural landscape - The Elms Historic Area - that is one of the best-preserved mission sites in the country. The buildings are associated with related structures, buried archaeological deposits, and historic plantings from one of the longest-surviving gardens in New Zealand. The buildings are particularly valuable to the city of Tauranga due to their links with the town's establishment. The structures enjoy high public esteem for their rarity and age, and as icons of early missionary activity in the region.