The Wangal clan or tribe were documented as having occupied the southern side of the harbour from Long Cove to Parramatta and Rose Hill.

Records from neighbouring areas would suggest that the Wangal would have actively participated in river fishing, eeling, gathering shellfish as well as hunting kangaroos, wallabies and other small land mammals, reptiles and waterfowl.

[1] Land grants in the area started as early as 1797 after an exploration party with Governor John Hunter up the Parramatta and Duck and George's Rivers.

Shortly after, two officers, formerly of HMS Sirius, Lieutenant John Shortland and Captain Henry Waterhouse, each received a grant of 25 acres, which they stocked with animals especially brought from the Cape of Good Hope (South Africa).

The area was included in a grant of 1290 acres made in 1807 to John Blaxland (1769-1845), who arrived in the colony that year, as a wealthy free settler.

The house was and remains an integral element in a landscaped setting (with the chapel off to its eastern side) which has been somewhat altered over time due to its location in the grounds of a correctional centre.

After Blaxland's death the property was used to manufacture salt and slaughtering, the home's kitchens were converted into a piggery and its once beautiful dining room used as a barn[3]- the house was considerably neglected.

[1] The house had carriage loops to its east and north with 2 prominent hoop (Araucaria cunninghamii) and Norfolk Island (A.heterophylla) pines, garden beds cut into lawn areas and spikey plants (e.g.: Agave sp.

A 1953 photograph from the same location shows the hoop pines gone and 3 prominent Canary Island palms (Phoenix canariensis) east and north of the house.

Marnton, a Wesleyan minister who had served as chaplain at the penal colony of Port Arthur and later founded Horton College at Ross, in Tasmania's midlands.

He was appointed Principal when the establishment of the new school was finally approved by the Church in January 1863 and served in this role until his untimely death in the following year.

[5][1] The old bell, which had summoned Blaxland's convict servants, now called the boys to lessons, and free hours could be spent roaming the surrounding gardens and parklands.

A 1953 photograph from the same location shows the hoop pines gone and 3 prominent Canary Island palms (Phoenix canariensis) east and north of the house.

This has included large areas of ground grading and addition of extensive amounts of fill (contaminated soil and subsoil), formed into landscaped spiral mounds.

[1] A new Mental Health Assessment Unit and Clinic was approved in early 2004 as part of a current program to improve facilities at MCC.

Newington House was one of the subjects of architect and writer William Hardy Wilson's romanticised drawings of colonial architecture in NSW published in the 1920s.

[1] Archaeological excavation and monitoring has revealed deposits and features relating to the construction of Newington House, in addition to aspects of its alteration and refurbishment.

[1] The quantity and form of the bricks and mortar suggests it is likely that the building materials for the house, cellar, verandah and cavity fill were manufactured on site.

[1] Close to the house's northwest corner is an extremely rare shrub or small tree specimen, reputedly planted c.1840 during the Blaxland residency, the South African species Boer or Hottentot bean (Schotia afra, family Caesalpinaceae), related to the parrot flower tree (S. brachypetala), itself rare in NSW.

This former walkway planting may date to the 1860s–1900, the main period of popularisation and fashionability of these species, and their promotion by such public figures as then Directors of the Royal Botanic Garden, Sydney, Charles Moore and Joseph Maiden.

The design has been described as Gothicised Georgian as it features not only pilasters, a string course and a pedimented gable but also Gothic Revival style pointed arches, rudimentary tracery with amber glass and quatrefoil vents.

The design of the building, probably by the Government Architect, Walter Liberty Vernon, draws on the tradition of military hospitals developed for hot climates.

The aesthetic values of the building are heightened by its setting as an individual building in an established garden setting, adjacent to a remnant landscaped walk formed by mature rainforest tree species and palms, including Moreton Bay fig (Ficus macrophylla), hoop pine (Araucaria cunninghamii), Bunya Bunya pine (A.bidwillii), cotton palms (Washingtonia robusta) and swamp mahogany (Eucalyptus robusta).

Immediately south of the chapel is a tree of heaven (Ailanthus altissima), possibly a sucker of an older specimen from the former estate or hospital periods.

[1] Silverwater Correctional Centre is of exceptional significance as: it is the core remaining part of John Blaxland's Newington Estate and of the State Hospital & Asylum for Women, for its subdivision and subsequent use for a variety of institutional functions, as an expression of a philosophy regarding the care of the aged.

[1] The building has aesthetic value in its relationship with the family chapel and with Parramatta River, although the latter has been diminished by landfilling operations on the former tip site to the north.

The remaining garden setting of the house, which includes the carriage loops, is also aesthetically significant notwithstanding the positioning of the Mulawa Correctional Centre security fence.

[1] An area of great historical interest and significance as the focus of the site containing the essential components of the original Newington House surrounds and chapel.

The significant elements include: The trees of significance in this precinct include a group of Araucarias (Bunya pines & hoop pines) and Moreton Bay figs (Ficus macrophylla) in the Mulawa Correctional Centre compound (remnant of a former landscaped walk to the river), the extremely rare Schotia afra (Kaffir bean, Boer bean) and the surviving turpentines (Syncarpia glomulifera) which are likely to be indigenous to the site.

[1] The cottage has historic and aesthetic values as a good example of Federation domestic architecture and particularly of the work of the Government Architect's office in the time of Walter Liberty Vernon.