Accompanied by his wife and four of his six sons, William Cox the elder departed England for New South Wales in 1799 in command of a detachment of the NSW Corp on the convict ship Minerva.
The Minerva carried 165 male convicts and 26 female prisoners.
William Cox of Hobartville son of William Cox the elder of Clarendon first arrived on the Experiment in 1804. He purchased a commission in the New South Wales Corps in 1808 before returning to England with that regiment, being promoted to Lieutenant in 1812. He returned to the Colony in 1814 on the Windham as a member of 46th Regiment; he purchased the estate of Hobartville near Richmond in 1816. 
Edwin James Brady in Australia Unlimited published in 1918 tells of the Cox family......
In 1819 Mrs. William Cox died, leaving five sons, and two years later Mr. Cox married again, adding to his family three sons and a daughter. William Cox (the elder) died in 1837 at the age of 72 years, leaving behind him a reputation second to none among those grand old pioneers who laid the foundations of the Mother State. His numerous sons, too, left their names on the records of the early pastoral development of the State, and themselves left large families of worthy descendants to the present generation. It may be briefly stated that of William Cox's first family
1).William Cox, junr. - who served as a young officer in the Peninsula War - came out to New South Wales and married the daughter of Captain Piper, after whom Point Piper, Sydney, was named. He founded Hobartville, near Windsor, and afterwards took up station properties near Muswellbrook and near Warialda.
2).George inherited Clarendon (which Chas. H. Cox, J.P. was afterwards sold by his son, Charles Clarendon, to Mr. Arthur Dight), and himself founded Wimbourne. He married Elizabeth, the daughter of Lieut. Archibald Bell, of 'Bell's Line' fame.
3). James went to Tasmania and founded Clarendon, near Launceston.
4). Henry possessed much property in the Mudgee district.
5). Edward lived and died at Mulgoa.
Of the second family, Edgar inherited 'Hereford.' Thomas became a clergyman and went to England; he inherited some Sydney city property from his father. Alfred became the owner of 'Burrandong,' but sold it and settled in New Zealand. The daughter married Captain Isherwood and moved to England.
In Dawn in the Valley, W. Allan Wood gave details of William Cox and the Negoa estate: -
William Cox the elder of Clarendon and his son William Cox of Hobartville, between them purchased 8000 acres to form the estate of Negoa. William Cox of Clarendon who made the Blue Mountains Road to Bathurst, was authorised on 3 May 1825, to purchase 4000 acres and William of Hobartville was permitted to purchase an equal area by an order dated 23 June 1825. When William the elder had completed the purchase of some of this land he sold it to William of Hobartville, who purchased the remainder of his father's reserve to complete the 8000 acres in Negoa. 
On 9th March 1846 William Cox (of Hobartville) divided Portion 3 (2560 acres) and Portion 4(1280 acres) between his sons, William (third generation William), John Hobart and Sloper.
A cottage was to be built on the Negoa estate by William Cox of Hobartville in 1845 - Bricks, lime, cedar, hardwood, shingles were required to be supplied by the contractor 
February 1846 Family Notice - Sydney Morning Herald - Married, On Tuesday the 24th February 1846 by Rev. T.C. Mackinson at St. Thomas Church, Mulgoa, John Hobart Cox, Esq., of Negoa, Hunter River, second son of William Cox Esq., of Hobartville, to Eliza Georgina, eldest daughter of George Cox, Esq., of Wimbourne, Mulgoa (4)
Eliza Georgina and John Hobart Cox produced twelve children over the next twenty years.
Descendants of William Cox the elder are now settled in Queensland and in the northern parts of New South Wales. Charles Hobart Cox, J.P., of 'The Oaks,' Muswellbrook, is the third son of John Cox, who was the second son of William Cox, junr., of Hobartville. The latter married his cousin, Georgina, the daughter of George Cox, of Wimbourne, who had married Miss Bell and had eight sons and four daughters. John Cox had Negoa, near Muswellbrook, which still belongs to his three daughters, and also the Well Station, near Muswellbrook, of which his son, Charles Hobart Cox, bought half at his father's death and named 'The Oaks,' there being many oaks growing in the creek which runs through the property. It is nine miles from Muswellbrook, and consists of 3,500 acres of basalt country, undulating, with creek flats, and is timbered with box and currajong, with a sprinkling of ironbark. It carries a good flock of Lincoln crossbred sheep, and a few cattle and horses......... -
Australia Unlimited by Edwin James Brady
The Oaks Estate. There is a charm, not in ' the pathless woods,' that Lord Byron's misanthropic spirit craved for, but in a homestead and estate where trees abound, where the art of the builder, the gardener, and the stockbreeder combine and blend natural and artificial beauty' into one harmonious whole. That is the impression one naturally feels jn glancing at the homestead, the crossbred lambs, the ewes and weaners, and the dairy herds in the paddocks, of the Oaks Estate, the property of Mr C H. Cox, on Coal Creek, about eight miles west of Muswellbrook, in the Hunter River district of New South Wales. The property is a charming one in every way - the homestead is embowered amidst ornamental and fruit bearing trees, and the tennis court, hedged and fenced as part of the garden, orchard and grounds, give a completeness to the view that is not often obtained. So, too, with the sheep and the Iambs, and the cattle in the paddocks. There are the stock in pastures up to their bellies; there is plenty of grass in the paddocks, and also trees for shelter, for breaking the winds and receiving the showers and torrential rains. The Oaks Estate comprises about 4000 acres of practically all cultivatable land ; about 300 acres are under crops, 200 of which grow lucerne - used principally for topping up the sheep and lambs for market. The estate was formerly part of the Negoa property. Negoa was taken up by Mr. William Cox, of Hobartville, who knew good land when he saw it. So, too, with Mr. C. H. Cox; for not only are nearly all the 4000 acres agricultural land, but the estate is well watered, and capable of great things. As it is there are 4000-sheep on the estate, 2000 of which are breeding ewes, which in these times are not only a valuable asset to the owner, but of considerable importance to the whole country. Good breeding ewes on good pastures mean that the country will not be so long in stocking up as it was at one time feared. Mr. Cox has a small dairy herd, in addition to his sheep, but breeding and fattening sheep are his forte.
The following men were assigned to William Cox in the Upper Hunter district c. 1825 - 1840s. They were convicts and ex-convicts unless otherwise stated. Transportation of convicts ceased in 1840 and there were fewer convicts assigned
afterwards although many remained the district as they worked out their sentence until the 1850s.
Workers may not have remained on the same estates they were assigned to. They were often transferred or loaned to different farms and stations at harvest and shearing times. Convict labour played a significant part in the early development of estates such as Negoa and Segenhoe where men were employed as shepherds and shearers for the rapidly expanding flocks of sheep and also for clearing ground and
Mariner 1827; Segenhoe 1828; shepherd
Royal Sovereign; Muswellbrook 1838; farm servant
Mangles 1833. Negoa 1836
Hooghley1825; assigned to William Cox on arrival 1825
Neva 1833; Negoa 1838; labourer
?Colesby. Hunter River 1828; stock keeper
Marquis of Huntley 1828; Hunter River 1828; watchman
Countess of Harcourt 1828; Segenhoe 1828; shepherd
Andromeda 1830; Invermein 1837
Marquis of Hastings 1826; Invermein and Gwydir River 1833
Lloyds 1837; Muswellbrook; 1841
Portland 1833; Invermein 1837
Georgiana 1831; Invermein 1837
Lloyds 1833; Invermein 1837
Lady Harewood 1832; Invermein; 1837; shepherd
Surry 1831; Invermein 1837; ploughman, reaps, milks
Surry 1836; Muswellbrook; 1840
Vittoria; Invermein 1837; ploughman
Hooghley 1834; Invermein 1837
Henry Porcher 1825; Hunter River 1828; bullock driver; In 1833 employed as overseer
Prince Regent 1821; Hunter River 1828; sheep shearer
Bussorah Merchant 1828; Segenhoe 1828; shepherd
Lloyds 1837; Negoa 1838
Hadlow 1820; Hunter River 1828; reaper
John Barry 1821; Hunter River 1828; shearer
Countess of Harcourt; Hunter River 1828
Royal Admiral 1833; Muswellbrook 1840; farm labourer
Portland 1833; Invermein 1836
Southworth 1822; Hunter River 1828; shearer
Segenhoe 1828; ploughman
Asia 1822; Hunter River 1828; farm servant
Marquis of Hastings; Segenhoe 1828; watchman
Lady Feversham 1830; Muswellbrook 1839
Java 1833; Invermein; 1837
Came free per Charles Kerr in 1839; Hunter River
Portland 1832; Dartbrook 1832; ploughs, reaps
Hooghley 1834, Invermein 1837
Southworth 1822; Hunter River 1828; shepherd
Hercules 1802; Hunter River 1828; carpenter
Sophia 1829; Invermein 1837
Marquis of Hastings 1828; Upper Hunter 1834
Sheep overseer; Muswellbrook 1840; possible James Young who arrived free on the Earl Durham in 1837
Notes and Links
1). A narrative of proceedings of William Cox, Esq., of Clarendon, lately holding a commission in the New South Wales Corps or 102nd Regiment, in constructing a road from Capt. Woodriffe's farm on the Nepean River, opposite Emu Plains, over the Blue Mountains, and from thence to Bathurst Plains, on the banks of the Macquarie River, in the years 1814 and 1815 - National Library of Australia
 Colonial Secretary's Index
 Wood, W. Allan, Dawn in the valley : the story of settlement in the Hunter River Valley to 1833, Wentworth Books, 1972.