The farm diaries, which date from the late 1880s to the 1970s, are a complete record through that period of Waitangi Station, on the north bank of Lake Aviemore, in the Waitaki Valley.
They were given to the archive by Heather Sutton, whose husband John's grandfather, John Alfred Sutton, bought the station in 1887.
Mrs Sutton said she discovered the diaries in an unusual fashion in 1986.
"I needed some new hens, so I lifted out the hen house and found them [the diaries]. They were buried quite substantially.''
She stored the diaries in a wardrobe and took them with her when she moved from the station to Oamaru.
Mrs Sutton decided to donate them to the archive to ensure they could be well looked after for years to come and available to view.
"If they're in someone's home, they're not available.''
She was also in possession of her late husband's diaries, which recorded the station's activities from the 1970s until 2014.
"They [the archive] can have them when I die. I'm not prepared to let them go at the moment.''
Waitaki District Archive curator of archives, Chris Meech, described the diaries as "an amazing window into southern high country station life and a notable gift to the community''.
"I was thrilled because the history of this station is very important to the history of this district and it's rare to find a complete and unbroken historical record of life on an early runholding.''
The diaries had attracted interest from researchers at Waikato University.
Because of the delicate nature of the diaries, they would not be displayed publicly, but there are plans to digitise them to for online access through the Culture Waitaki website.
The Sutton family's sheep farming history has been continuous since 1854.
In 1884, John Alfred Sutton brought several Mackenzie country stations before he sold them in 1886 and bought Waitangi Station.
He died in November 1922 and is buried in Oamaru.
The more than 20,000ha Waitangi Station, which runs several thousand merino sheep and a few hundred cattle, is now run by Heather and John's son, David.
- Daniel Birchfield
