Sunnyside was originally a forty-acre (16 hectare) property purchased by Mrs. Ellen G. White, a co-founder of the Seventh-day Adventist Church, from the Avondale Estate (originally the Brettville Estate) owned by the church, in July 1895.  Later she expanded that to sixty-six-acres.  Her purpose in purchasing the property was to provide assistance and incentive to the developing educational institution, the “Avondale School”, owned by the Church.  The Sunnyside property is located in Cooranbong, N.S.W. which was then a small timber cutting town with a Post Office, Police Station, three hotels and two churches.

The first buildings built was a “wash house” and workshop, while the main house was being assembled.  Construction of the home began in August 1895 under the direction of master builder, J. G. Shannon who was originally from Tasmania. While building took place, Mrs White, her household and most of the building team lived in tents on the property.  Sunnyside was completed in early 1896 and the household was able to move from tents into the home on Christmas day, 1895.

The original house was a double story, 9.75 X 9.75metre building with a front veranda.  It had four rooms on each level, the lower having a hallway between them, with eleven rooms in all.  Attached to the rear of the main building, next to the dining room, were facilities for a kitchen, bathroom and storeroom.  Its construction reveals the American New England style and influence of its owner, Mrs. White, adapted somewhat for Australian conditions.

To show that the land was useful for agriculture, an orchard was planted consisting of stone fruit, apples, pears, citrus and grapes.  These began to bear fruit during the nine years of Mrs White’s stay at Sunnyside until August 1900.  A large garden of vegetables was also cultivated.  These were innovations for the area as it was believed the land was infertile. The Sunnyside property remains in the care and ownership of the Seventh-day Adventist Church and is visited by thousands each year.