The proximity to the Nepean River and South Creek qualifies it as a key area for food resources for indigenous groups.

Situated on fertile floodplains and well known for its abundant agriculture, Green Hills (as it was originally called) supported the colony through desperate times.

[1] John Bowman (1763-1825) arrived in NSW in 1798 and settled at Richmond, farming the property "Archerfield" which he received as a grant of 100 acres on 8 April 1799.

[2][1] Bowman quickly identified himself with the cause of free settlers on the Hawkesbury, opposing the monopolistic practices of the New South Wales Corps and supporting stable government as administered by Governors William Bligh and Lachlan Macquarie.

Their efforts were rewarded by the instructions given to Macquarie to give help and encouragement to the smaller settlers, and by the decline of the influence of the military during his governorship.

[1] When Macquarie had brought stability to the colony, and regained respect for the administration, Bowman concentrated on farming pursuits.

He died on 16 December 1825, and left his house to his son, George Bowman, who lived until 1878 and concerned himself with farming and grazing stock on the Hunter River, as well as with public affairs, being elected to the new Parliament of New South Wales in 1851.

[1][5] John and Honor Bowman had four children and their son William is listed in the 1828 census as having 300 acres at Richmond, with 137 of these cleared and 130 cultivated.

[1] In the 1830s William Bowman (the fourth and youngest child of John) became interested in the promotion of free immigration to the colony.

In 1837, to sponsor immigrants, he signed an agreement with John Marshall, captain of the ship City of Edinburgh, to pay for the passage of twelve married couples from London to Sydney.

Sam Boughton writing under pseudonym of "Cooramil" in the early 20th century claimed that George Marlin built it after coming under contract from England with his family.

George C Johston writing under pseudonym "Cooyal" disputed whether it was built by Marlin and claimed the builder was James Melville.

[7][1] William Bowman, along with his older brother George, played a major role in the development of the district, involved in pastoralism and farming and prominent in public affairs.

Toxana was a substantial town house erected at the height of the 1840s boom before depression meant straitened circumstances for many of the pastoral elite of the colony.

In that year Ann Cadell agreed to sell Toxana and 8 acres of land in Windsor Street to Rev.

[1] Photographs from 1888 show the front of Toxana obscured by a large jacaranda (Jacaranda mimosifolia) tree on the eastern side and an even larger pair of trees on the western side - these appear to be a silky oak (Grevillea robusta) and a Southern nettle tree/ hackberry (Celtis australis).

The front fence at this time was a low masonry wall, with stone pillared gate posts; a wrought iron and "crinkle wire" gate; and low wrought iron balustrade (possibly infilled with wire mesh) atop the masonry wall - the whole below 1m high.

The College was officially opened on 16 March 1891, a photo[9] shows the Ministerial party and others on Toxana's front steps.

[11][1] The College gave scientific and practical training to aspiring young farmers, and had acquired land just out of Richmond.

[13][14][1] A draft conservation plan for Toxana prepared by Graham Edds & Associates provided a series of historic photographs over the life of the building which reveal change in the landscaping of the forecourt since c. 1842.

This photo also clearly shows the large jacaranda and silky oak trees part-obscuring the house's street front.

After two parcels of land, part of that property, were transferred in 12/1934 a new certificate of title was issued on 22 February 1935 to Mulvena, who was then living in Marrickville.

RAAF headquarters requested that Stocks be allowed to remain due to the rapid expansion of Richmond air base and the difficulty of obtaining accommodation.

[20][1] In 1978 Toxana was bought by Windsor Municipal Council for $75,000 and restored at a cost of $179.500 with assistance from the Commonwealth Government grants program.

A series of photographs from before 1978 are held at the Hawkesbury City Library's local studies collection and document the state of the building before conservation work commenced.

[20] Another series of photographs held in HCL's local studies collection document the 1978 restoration works to the building.

[22][1] Toxana was given a Permanent Conservation Order under the NSW Heritage Act on 23 July 1979 and entered on the Register of the National Estate on 21 October 1980.

The house is built of face brick with sandstone quoins and reveals, as well as heavy stonework surrounding the front door.