Isaac Haig was the second son of I. Haig, Esq., of Bemersyde, in the county of Berwick Scotland. He arrived in Port Jackson on 28 September 1839 on the Duncan having departed London on 29th May 1839.
Isaac Haig was residing in the Scone district in 1840 when a young man named John Graham was shot and killed by members of the Jew boy gang. Dr. Haig was called to examine the body and found Graham had died of internal haemorrhage caused by a gunshot wound. He later testified at trial that no medical intervention could have saved John Graham.
Governor Gipps' Visit to Scone
Sworn in as Magistrate in February 1844 and a respected member of the community, no doubt he was among the gentry who welcomed the Governor later in November that year. The district had excitedly prepared for the visit of Governor Gipps who was to travel to Scone with his wife and their entourage. The anxiety over the time of his arrival 'manifested beyond conception and evinced the greatest loyalty towards her Majesty's representative.'
Many of the settlers of the district sent invitations to the Governor to partake of their hospitality. John Bingle from Puen Buen made great additions to his house thinking the Governor might stay there. On the morning he was expected, a great number of gentlemen headed by respected clergyman Rev. John Morse proceeded at 7am towards Aberdeen hoping to meet his Excellency and suite; however Governor Gipps, upon reaching Aberdeen became ill and was compelled to take to his bed. He was attended by Isaac Haig and Joseph Docker who remained in attendance and in the Governor's company until he was able to resume his journey.
Isaac Haig later established a hospital at Tamworth.
In 1850 Richard Lewis Jenkins of Woolowin took over the practice:
'The undersigned begs to intimate to the residents of Liverpool Plains and adjoining districts that he has made arrangements to remove from his Station to Tamworth, to succeed to the Practice of Dr. Haig. In compliance with the wishes of several respectable settlers a Hospital will be established for the conveniences of Invalids resident in the interior. Richard Lewis Jenkins, L.A.C., and Member of the Royal College of Surgeons, London. Peel's River, Jan 10, 1850'.
Isaac Haig died on 29th February 1852 at his residence 218 Castlereagh Street, age 46. 
Coroner's Inquest - The coroner opened an inquest at the Sir Maurice O'Connell Inn, Elizabeth and Hunter streets, on view of the body of Dr. Isaac Haig, then lying dead at Mrs. Mein's boarding-house, in Elizabeth street. The following evidence was adduced. Elizabeth Fitzsimmons, a servant of Mrs. Mein's, stated that deceased arrived in Sydney from Melbourne on Sunday last, in the brig Clara ; witness knew him about nine months ago, when he lodged with Mrs. Mein. He had been absent from Sydney about two months, and on his return appeared to be in excellent health ; he conversed for some time with Mrs. Mein, and then went upstairs to his bed-room ; witness soon after heard a great noise, and upon running to ascertain the cause, found deceased supported by Mrs Mein upon the stairs. He said that he was hastening down, as he feared he was about to be attacked by a fit; he was removed into a room, and Mr. Aaron was immediately sent for, but deceased died shortly after his arrival.
Witness was questioned as to deceased's property and will, but of these she was only enabled to speak by hearsay. Mr. Isaac Aaron, surgeon, stated that he was called in on Sunday, between 12 and 1 o'clock, to see the deceased ; on his arrival deceased appeared to be moribund ; he was insensible, his extremities cold, and he was pulseless. Witness used such remedies as he thought requisite for the time being, and sent for Dr. A'Beckett. Deceased died in about three quarters of an hour after the arrival of witness. The cause of death could not be told by witness in the absence of a post mortem examination. Witness supposed that death was the result of disease of the heart ; there was nothing externally apparent, that the witness was aware of, indicating rupture of an internal blood-vessel.
The Coroner then adjourned the inquest until yesterday at noon ; when he called Dr. A'Beckett, who stated that he was called in on Sunday last, about 1 o'clock P.M., to see the deceased, who was then pulseless and in a dying state. Mr Aaron was in attendance ; heat was applied, and a little brandy was poured into the mouth of deceased, with no avail ; he died shortly afterwards ; he, Dr. A'Beckett had never seen deceased previously, and could form no positive opinion as to the cause of death, but suspected disease of the heart ; there were some doubtful points about the case as to the cause of death ; it was not a clear case ; in any cases of approaching death, similar symptoms might be exhibited as those which were shown by the deceased ; he was a man of moderately full-habit, and in pretty good condition ; by order of the Coroner, he, Dr. A'Beckett, had made a post mortem examination of the body ; the heart was extensively diseased, and empty of blood; in his opinion, deceased had died from asphyxia ; he had examined no other organ than the heart, considering its appearances quite sufficient to account for the suddenness of death ; any cause of excitement would accelerate death ; generally, one side of the heart contains blood, but in this case the heart was wholly empty. The jury found a verdict of ' died by the visitation of God.' 
Isaac Haig was buried in the Camperdown cemetery 
4). Isaac Haig - Name of Run Dungowan. Estimated area, twenty five thousand six hundred acres. Estimated grazing capabilities, eight thousand sheep. The valley of Dungowan creek from its sources in the great dividing range to its confluence with Peels River having a frontage upon that river of about four miles above the said junction and one mile below it; the boundaries on the north and south being the ranges that divide the creek from the neighbouring streams, the frontage on the river commences at Redbank and extends to the eastern boundary of the Pillamore station, namely a deep red gully, about a mile below the junction of Dungowan creek and Peels River. - Claims to Leases of Crown Lands Beyond the Settled Districts - Liverpool Plains District The Sydney Morning Herald (NSW : 1842 - 1954) Tue 26 Sep 1848
 Sydney Morning Herald 1 March 1852
 Ancestry.com. New South Wales, Australia, Unassisted Immigrant Passenger Lists, 1826-1922