Heritage New Zealand's Fundraising Manager, Brendon Veale, said personal notes were often sent in by supporters with their donations.
"These notes show the affection people have with Pompallier Mission. It's not just a building to them. It has a direct connection - a happy memory that they want others to have a similar opportunity to experience by visiting. And these messages are not just local; they are from all around the country."
Built in 1842, Pompallier Mission is a Category 1 historic place established by French Catholic missionaries as a tannery and printery, translating church texts from Latin to te reo Maori.
"I think the connection our visitor host, Airini Kingi, has with Pompallier also struck a chord with donors during the campaign," Mr Veale said.
"It was Airini's father who, in the late 1980s, uncovered the tannery pits at Pompallier during an archaeological dig that helped us understand the significance and history of the place that much more. So many people have a story or connection to Pompallier Mission."