St Isidore's is a heritage-listed homestead at 40 Post Office Road, Mapleton, Sunshine Coast Region, Queensland, Australia.

[1] This substantial, high-set timber residence was erected in the early 1900s in at least two stages, for pioneer Mapleton orchardist William James Smith and his family, at their Seaview Orchard at the top of the Blackall Range.

[1] WJ Smith and his brother Thomas David were the first to take up land in the Mapleton district, and had an important association with fruit-growing in Southeast Queensland in the late 19th and early 20th centuries.

In 1889 WJ and TD Smith, both in their early twenties, explored the Mapleton district (then unnamed) on the Blackall Range, in search of land suitable for banana growing.

In 1889 the North Coast railway line was completed as far as Caboolture, and a coach ran to Noosa, but the only way into the Blackall Range was by foot.

[1] In September 1891 WJ Smith married Sarah Anne Imogene (Annie) Collins, whose family were Redland Bay settlers, and the couple returned to the Blackall Range.

In mid-1892 Smith selected the property which he developed as Seaview Orchard (portion 185v, parish of Maroochy, comprising just under 160 acres of dense vine scrub).

[1] For a brief period the district was known as Luton Vale, after a postal receiving office opened at EH Biggs' Lutonvale Orchard in January 1893.

By August 1897, when WJ Smith was applying for a title to his selection, the family was still residing in a 22-by-18-foot (6.7 m × 5.5 m), 4-roomed split timber dwelling with a shingled roof, valued at £20.

[1] The first section of Seaview House may have been constructed by October 1906, when the WJ Smiths hosted a luncheon in their barn for the Queensland Governor, Lord Chelmsford, during his brief tour of the Blackall Range.

[1] Timber used in the construction is likely to have been milled locally, WH Rosser having opened the Mapleton Sawmill, about 1 mile (1.6 km) northwest of the township in January 1909.

In 1914-1915 Maroochy Shire Council extended the former Moreton Central Mill tramline from Kureelpa to Mapleton to serve the Blackall Range fruitgrowers.

In 1919 they retired from citrus growing and moved to Northgate in Brisbane, but prior to their leaving the Mapleton district, they were accorded a public farewell and address.

The sale included Seaview House: a large roomy structure, with a delightful garden in front, artistically laid out, with graceful palms at the entrance.

However, Duhig's vision was not shared by the Brisbane diocese in general, who refused to finance the establishment of a Catholic agricultural college at Mapleton.

[1] By February 1947, when the National Catholic Rural Movement (NCRM) took over management of St Isidore's Farm College, aiming to bring it back into production and to establish an Agricultural Training College, there was no cultivation and no livestock on the farm, the property was overgrown with weeds, and its three houses, including the former Seaview residence, were in disrepair.

Within eight months, under a capable farm manager, fields of potatoes, onions and citrus trees had been planted, there were plans to begin softwood silviculture, and an additional 150 acres had been purchased.

Known as Mapleton Homestead through the 1980s, it functioned as a private residence until opened in 1990 as Sea View Guest House, run by the MacDonagh family, and later by the O'Briens.

[1] St Isidore's is a large, high-set timber residence, situated on the eastern edge of the Blackall Range, at Mapleton.

[1] St Isidore's presents an aesthetically pleasing exterior, engendered largely by its complex hipped roof clad with corrugated iron sheeting (not the original), and decorative timberwork to verandahs and gables.

A late 20th century deck extension off the enclosed eastern verandah, with its side entrance, has a replica gabled portico and steps, echoing that on the front elevation.

[1] There have been a number of alterations to the rear (north) elevation, including the addition of a skillion-roofed, weatherboard-enclosed bathroom at the western end, and a recent breakfast room off the kitchen.

[1] Externally, the house suggests a symmetrical plan, but internally, the rooms are arranged in an idiosyncratic fashion, reflective of its construction in at least two stages.

Many of the designs are Art Nouveau in inspiration, including that of the dado panels in the vestibule, which has been identified in an early 20th century Wunderlich catalogue.

The place is significant for its association with WJ Smith and his family and their important contribution to the establishment and growth of Mapleton and to the development of fruitgrowing in Queensland in the late 19th and early 20th centuries.