Fernhill is a heritage-listed former chicken hatchery, plant nursery, guest house, farm, residence, stone mason's yard and piggery and now residence and horse stud located at 1041 Mulgoa Road, in the western Sydney suburb of Mulgoa in the City of Penrith local government area of New South Wales, Australia.

[3] Set on 690 hectares (1,700 acres), Fernhill was built as a much grander residence with associated gardens following Cox's earlier construction of The Cottage, that dated from c. 1810.

[7][3] The first land grant was made by Governor Macquarie to Lieutenant William Cox, a colonial magistrate who promptly registered the property in the parish records in the name of his infant son, Edward.

[3] Fernhill estate is located principally on the first land grant made in the Mulgoa Valley (to the infant Edward Cox) dating back to 1809.

During his 37 years of residence in the early colony, he made a substantial and enduring contribution to its progress in the fields of public administration, building and agricultural development.

In 1827 he married Jane Maria Brooks (of Denham Court estate, Ingleburn) and the family lived at The Cottage, Mulgoa (to the east) for many years.

It was planned on a large and sophisticated scale and in the Greek Revival style, possibly by colonial architect Mortimer Lewis.

[14][3] Lewis' private commissions show a dependence on published sources, identified in recent year by architectural historian James Broadbent.

Their plans are probably adapted from the British architect William Wilkins' design for "Oxberton House", Nottinghamshire, as published by George Richardson in the New Vitruvius Britannicus (1802-8).

[10][3] Twenty Irish stone masons were brought out to Australia under the bounty system of immigration for the specific purpose of building the Fernhill house, using sandstone quarried from the local hills.

[3] In the early 1850s the estate was singled out by Governor FitzRoy's aide-de-camp, Col. Godfrey Mundy, for the way in which its landscape had been moulded by thinning the native species.

[24][3] Fernhill is in (on the western side of the middle of) the Mulgoa Valley, a picturesque rural landscape retaining a number of significant colonial and later 19th century farm estates, building complexes and areas of natural bushland.

It is characterised by predominantly rural landscape and comprises creek flats, gently sloping agricultural land, wooded hills and escarpment areas.

The road continues across two small decorative but massively constructed balustraded bridges and winds upwards below the now partially obscured garden front of the house.

Mundey's nineteenth century description of Fernhill's landscape being the finest piece of English park like scenery, but with Australian species, in New South Wales, is still arguably true.

They were unnecessary in an engineering sense as the drive could have been constructed higher up the hill to avoid the shallow gullies which the bridges cross.

and runs in a relatively straight line up hill, compared to original (southern) driveway, with its carefully contrived bends to reveal views and hide them.

[27][3] The northern of the two existing drives passes an orchard plantation area of pecan (Carya illinoiensis) trees and a large rock-faced stable structure to the north.

Reportedly timber piling was removed in c. 1980 works and lined with (quite dramatic and tall) stone walling which has changed its character.

This was replaced with a car court hidden below a retaining wall to the north-east of the house with an approach stair arriving at lawn level near a grove of Chinese elms at the end of an enormous pergola.

In this pergola Sorensen (/Darling) reused old architectural elements, sandstone columns from the Union Club, Bligh Street, Sydney (demolished in the early 1960s to build the Wentworth Hotel).

Later works included provision of an ornamental pool (the dam with island east of the house) and the transplanting of an ancient evergreen magnolia/bull bay (Magnolia grandiflora) from Sydney into the garden.

[35][3] Substantial drain with dished bottom and stone sides and top running from back (west) of house under south end of old stable.

The three buildings were originally linked by tree-lined drives, the remains of which bear evidence of an attempt by Cox to create an English-style rural landscape in an Australian setting.

The native trees of the area include Angophora subvelutina, a species which approximates the English Oak in size and habit.

Sham porte cochere (timber and flat sheeting) added c. 1900 was removed (in poor repair with termites), showing up the original arched stone entrance.

[3] The Fernhill estate comprises an extensive area of modified and natural landscape which provides the setting for a house completed c.1845 for Edward Cox.

[3] This group of three sites retain their original visual relationship to each other and demonstrating the ambitions and changes in wealth and status of an important early colonial family (the Coxes) from 1810-1880s.

The landscape is significant for the high degree of creative design achievement, attributed to the original owner, Edward Cox.

[43][3] The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales.