Sixteen armed stockmen on horseback were in an alleged battle with Gamilaraay warriors. More than six Gamilaraay people were killed, and the stockmen suffered no casualties (Reece 1974, p 28-9).

Sergeant Temple led a detachment of mounted police and a party of stockmen and settlers, including TS Hall to 'clear' the Barraba area of Aboriginal people. Missionary LE Threlkeld said that 80 Aboriginal people were slaughtered (Gunson, 1974, 136). The operation was briefly reported in British Parliamentary Papers for 1839 (BPP 1839, Paper 526).

Conflict in the Gwydir region intensified in 1837 including armed attacks on Gomeroi people to abduct women, and the killing of livestock and 5 colonists by Gomeroi people in several incidents (Milliss, 1992, p 159).
Men at Mr Bowman's station were killed by Gomeroi people as punishment for abducting women. Henry Bingham reported that 'I am well informed those men armed themselves with Muskets and made a rush, on the camp of those Blacks in order to deprive them by force, of their women and in revenge for this they have fallen sacrifice to their own lawless conduct' (Bingham, cited in Milliss, 1992, p 153). The killing of these men prompted the massacre of a large number of Gomeroi people at Gravesend.
In 1837 Missionary L.E. Threlkeld wrote of a massacre preceding the killing of two more shepherds at Anambah which is probably the Gravesend massacre: 'two shepherds of Mr Cobb's station, Anambah,' on the Gwydir River, 'who were unfortunately murdered by the Blacks, suffered it is said, in consequence of the atrocities being committed against the Blacks by the stockmen in another part of the country, which drove them towards Mr Cobb's station, where they met the two shepherds and wreaked their vengeance, in retaliation, on the unhappy sufferers.: so I am informed by one who was there at the time of the catastrophe' (Threlkeld in Gunson 1974, vol.II, p.145).
A chronology of killings of colonists records the date as November, 1837 (The Sydney Herald, 10 Dec 1838, p 2).
Milliss discusses the Gravesend massacre in his book Waterloo Creek: 'In evidence given in 1839 Mayne reported that a "dreadful massacre" was said to have been committed by stockmen in which as many as 200 Aboriginal people were killed. According to Milliss, Commissioner Edward Mayne 'gave no date for this massacre, except to say that it had taken place "previous to the murder of the two shepherds at Mr Cobb's station", which was itself, reputedly "done in revenge for another outrage of a similar kind upon the blacks"' (Mayne cited in Milliss 1992, p.159).
Mayne's evidence to the Committee on Police and Gaols is as follows: 'I was encamped with various of the tribes in my District for about three months; there were at times 700 collected together, from a distance of one hundred miles. They were induced to come in and collect together from the messages I sent to them; there is at times great difficulty in inducing them to come in. I was anxious to have an opportunity of explaining to them the object of my coming among them; they seemed much pleased when I did so explain. Between the Rivers Namoi, Peel, and Gwyder (or Big River) there is a Black Native Population of between 2,000 and 3,000 persons. When I arrived in that part of my District, such was the want of confidence subsisting between the Whites and the Blacks, that wherever they encountered each other, the Whites expected themselves or cattle to be speared, and the Blacks expected to be fired at. It seemed to be the general impression among the Overseers and Stockmen in the Upper District, that the Namoi and Gwyder Blacks would unite and make a general attack on the Herds and Stations. I think it probable there were grounds for that impression. I consider that the desire of revenge on the part of the Blacks originated in various outrages committed on them by Stockmen and persons of that class. Previous to my arrival in the district, I believe many instances occurred in which the whites fired upon the Blacks when merely meeting them on the runs. I am informed that the whites have been known to rush them in the scrubs, and to fire upon their women and children; and that the Stockmen and Hutkeepers always went about with fire-arms. I issued a notice, cautioning the Stockmen from appearing with arms; it was obeyed, and acknowledged by themselves generally to be attended with the best effects. I caused it to be explained to the blacks, and it tended much to a more friendly and confidential feeling between both parties than had yet been exhibited. Previous to this, there were few of the runs that the blacks dared not show themselves upon without being either fired at, or hunted off like native dogs; nor were they permitted to approach the rivers without being subject to attack. I have scarcely ever seen joy more strongly depicted in any countenances, than in those of the blacks when I assured them that they might again fish quietly in the rivers without being driven away. I have found such accounts and information as I have received from time to time from the blacks to have proved substantially true. I would instance particularly the case of the murder of the blacks which took place near to Mr. Crawford's station, called Ardgowan Plains, situated on the Gwyder or Big River, and which was afterwards fully corroborated on oath by an approver. This murder took place about twelve days before Mr. Cobb's two shepherds were murdered by the blacks; about 1,000 sheep were destroyed at the same time. The blacks informed me that this was done in revenge for the murder in question. They explained the delay to have arisen from the difficulty of getting all the tribes together sooner; there was, in fact, a much larger number of blacks assembled on that occasion than usual; the reports of some of the shepherds say 1,000. Great excitement prevailed at that time among the blacks. I believe two or three attacks had been made on them by the overseers and stock men within a few weeks on that part of the river. They stated, that finding it impossible to retaliate on the mounted stockmen, they determined to attack the shepherds and sheep. I conceive that the outrages committed upon the blacks were provoked in the first instance by their having speared cattle. The first outrage that I heard of occurred about two years ago. I consider that a good impression has been made upon the blacks by the late proceedings, and that a good opening has been made for the reception of a Protector amongst them. They complained in some instances of the white men interfering with their women, which appears to have been very common formerly; yet there is no doubt that they frequently lend them for a time; but even this is not done without a degree of jealousy, and more or less ill-feeling is likely to be engendered by it. There are some cases of black women living with white men who have families by them, some of whom it will perhaps be necessary to allow to remain, as they would probably be killed if forced to return to their tribes, some of them also have become attached to the men they are living with, and would be unwilling to leave them. There are various reports of a dreadful massacre, said to have taken place some years since, in which the stockmen are stated to have killed a great number of blacks; I have heard it said, as many as 200 were killed on that occasion. I saw the place in which they are are said to be buried. It is known by the name of Gravesend from the number of appearances of graves. This massacre is said to have taken place previous to the first murder of two shepherds at Mr Cobb's station, and which, it is reported, was done in revenge for another outrage of a similar kind upon the blacks. Gravesend is a high mountain, situated about three miles from Mr. Cobb's head station on the Gwydir or Big River. I always issued the strictest orders to my men not to interfere with the black Women; any man doing go in the camp would have been instantly put into irons.' (Mayne, Evidence to Committee on Police and Gaols 5.9.1839, pp 22-24, V&P 1839, V&P pp 22-24)
Mayne's version makes it clear that unusually large numbers of people could have been killed. He estimated 2000 to 3000 Gamilaraay lived in this region and he had witnessed up to 700 gather at a time. The war party against Cobb's Station was said to be 1000 strong. Mayne mentions that 'I believe two or three attacks had been made on them by the overseers and stock men within a few weeks on that part of the river'. From the slightly disjoint narrative, it's not clear if Mayne is describing the same, or two two distinct events at Ardgowan Plains and Gravesend in the lead up to the killing of shepherds at Cobb's station.

The massacre at Anambah Station is part of an extended conflict. Two shepherds were killed at Mr Bowman's for abducting Gomeroi women. This prompted the Gravesend massacre. In response to this Gomeroi people killed two shepherds at Cobb's Station at Anambah. Stockmen from Cobb's Station then pursued and killed Aboriginal people thought to be responsible for the murder of the shepherds (Milliss 1992, pp 158-159).
A chronology of killings of colonists records the date as November, 1837 (The Sydney Herald, 10 Dec 1838, p 2).
According to Threlkeld, 'The two shepherds of Mr Cobb, who were unfortunately murdered by the Blacks, suffered it is said, in consequence of the atrocities being committed against the Blacks by the stockmen in another part of the country, which drove them towards Mr Cobb's station, where they met the two shepherds and wreaked their vengeance, in retaliation, on the unhappy sufferers.: so I am informed by one who was there at the time of the catastrophe. Their fellow servants armed themselves, overtook or came upon the tribe, found some with clothes of the murdered shepherds on their backs, whom they hewed to pieces with their hatchets, and killed others' (Threlkeld in Gunson 1974, vol.II, p.145).

On 26 January 1838, twenty six mounted police under the command of Lt Cobban and accompanied by several stockmen and settlers drove a party of Gamilaraay warriors into Snodgrass Lagoon, now known as Jews Lagoon, and shot and killed at least forty of them. The massacre was allegedly in reprisal for the spear wound of a mounted police trooper two hours earlier. The massacre took place at the end of a month-long operation by mounted police in search of Aboriginal warriors led by Major J W Nunn (Milliss 1992, pp 183-96). In the ensuing inquiry into the massacre, Sergeant John Lee said that 'from forty to fifty blacks were killed.' (HRA, I, XX, p 251). A party of local squatters who visited the site later reported that 'sixty or seventy' Aborigines were killed, 'some of them ... shot like crows in the trees.' (SMH, 2 July 1849, p 2) The Rev. L. E. Threlkeld, (Gunson 1974, vol 1, p 145) in his annual report for 1838 to the NSW Colonial Secretary, said that 'two or three hundred' were killed. This number could be the tally of Nunn's month long operation against Gamilaraay people in the region.

On the 5th of September, 1839, Edward Denny Day, Police Magistrate of Muswellbrook gave evidence to the Committee on Police and Gaols. He spoke of the country being in a state of warfare and mentioned three massacre sites prior to the massacre at Myall Creek: Vinegar Hill, Slaughterhouse Creek and Gravesend, committed by groups of mounted and armed stockmen:
'It was represented to me, and I believe truly, that the blacks had been repeatedly pursued by parties of mounted and armed stockmen, assembled for the purpose, and that great numbers of them had been killed at various spots, particularly at Vinegar Hill, Slaughter-house Creek, and Gravesend, places so called by the stockmen, in commemoration of the deeds enacted there' (Day, Evidence to Committee on Police and Gaols 5.9.1839, p 224).
Descriptions of the massacre at Slaughterhouse Creek often describe it as an extended expedition of colonists aiming to finding and kill Aboriginal people. The headwaters of Slaughterhouse creek and the mouth of Slaughterhouse Creek, where it joins the Gwydir River at Biniguy, are both mentioned as massacre sites. Since this was an extended expedition it is reasonable to think both of these locations are massacre sites rather than it being one or the other. In Day's evidence, he mentions Vinegar Hill as a separate site to both Slaughterhouse Creek and Gravesend. Gravesend is a site reported by others. In his notes on p 811, Millis suggests 'Vinegar Hill' may be Biniguy or 'Binegar' (Millis, 1992, p 811). The word is phonetically similar, so colonists may have, after the massacre, corrupted the name to associate it with the Vinegar Hill uprising in the early colony of Sydney, named in turn after a battle in the Irish uprising, or Denny Day or the court scribe may simply have misheard it as 'Vinegar'. No other likely location for 'Vinegar Hill' in this region has been identified.
See Slaughterhouse Creek.

On the 10th of September, 1838, Edward Denny Day sent a letter from the Muswellbrook Police Office to the Colonial Secretary in relation to the Myall Creek massacre. This letter described a 'war of extermination' in the area around the time of the Slaughterhouse creek massacre: 'It will be my duty in my next letter to offer with the permission of his Excellency some observation on the present lawless state of the neighbourhood of the Big River [Gwydir River]. Indeed I am almost justified in stating that a war of extermination has been carrying on there against the blacks who neglect no opportunity of retaliating by destroying the cattle of the settlers' (Day, Letter to Colonial Secretary, 10 September 1838). 'Big River' was the early colonial name for the Gwydir River.
On the 5th of September, 1839, Day as Police Magistrate of Muswellbrook gave evidence to the Committee on Police and Gaols. He spoke of the country being in a state of warfare and mentioned three massacre sites prior to the massacre at Myall Creek: Vinegar Hill, Slaughterhouse Creek and Gravesend, committed by groups of mounted and armed stockmen:
'I was engaged during part of the last year in inquiring into the circumstances of the murder of a number of blacks, at the Big River, between two hundred and three hundred miles from the settled districts. I was engaged in the investigation and journey forty-seven days. That part of the country appeared to me to be in a most unsettled state; the whites seemed to feel that they were in an enemy's country, and were afraid to move out of their huts without fire arms, and the huts were provided with loop-holes, to fire through, in the event of their being attacked. The blacks had at that time committed many outrages; I think four stockmen or shepherds had been murdered, and cattle speared in great numbers on many of the runs; and sheep had also been driven away; but I have reason to know that these outrages had been fully and fearfully avenged. It was represented to me, and I believe truly, that the blacks had been repeatedly pursued by parties of mounted and armed stockmen, assembled for the purpose, and that great numbers of them had been killed at various spots, particularly at Vinegar Hill, Slaughter-house Creek, and Gravesend, places so called by the stockmen, in commemoration of the deeds enacted there. The murder I was sent to investigate took place at Myall Creek, Mr. Henry Danger's cattle station, where twenty-eight blacks���men, women, and children���were killed. The whole party of stockmen, twelve in number, who were engaged in this dreadful deed, were apprehended, except one; and seven of them were executed. At the time of my visit, the blacks and whites were alike exasperated against each other; in fact, the country was, I may say, in a state of warfare. It had been then occupied not much more than two years, and as the blacks were decidedly friendly at first, as was shown by their assisting in forming many of the stations, by stripping bark and in other ways, I can only account for the hostility that existed subsequently, by attributing it to the interference on the part of some of the stockmen with their women, which the blacks revenged on the first unprotected white persons who fell in their way' (Day, Evidence to Committee on Police and Gaols 5.9.1839, V&P 1839, p 224).
According to the author of the Wallabadah manuscript, most likely William Telfer, an early colonist in the area, 'the stations on the Mcintyre were not long occupied when the aboriginals began to be very hostile and to be agresive to the whites the cause was the Masacre of the blacks at slaughter house creek on the Big River where they ran the blacks into the Stockyard and destroyed them without mercy' (Telfer, 1980, p 37).
According to historian RHW Reece, (Reece, 1974, p.34), the Slaughterhouse Creek massacre was part of 'The Bushwhack or The Drive' that took place in the months following Major Nunn's expedition and the Waterloo Creek massacre on 26 January 1838.
A massacre at Slaughterhouse Creek is widely recorded in local oral history and folklore. Roger Milliss summarises the various accounts in his book Waterloo Creek (Milliss, 1992, pp 198-203) noting that some involve a detailed chronology. These accounts suggest that 'The Bushwhack... continued without let-up for four to five weeks, with men in the saddle day after day pursuing the hunt. But towards the end of May or early in June, as they swept across the east past Terry Hie Hie, they suddenly realised the blacks had slipped through the net.' Hearing of a hidden ravine, 'A party of fifteen heavily armed stockmen, so the story goes, made their way through the bush in the dead of night and quietly surrounded the gorge, in much the same way as Nunn and Cobban had set up their nocturnal ambush on the Namoi five months earlier. A large number of Aborigines, several hundred apparently, were asleep in the bed of the creek below. When daylight came the fifteen whites positioned on the steep slopes on either side opened up on them with muskets, carbines and shotguns, then clambered down and completed their murderous work with pistols, swords and cutlasses. Up to 300 people are said to have perished' (Milliss, 1992, p 202). As it was a long expedition, it is possible that killing occurred at both the stockyard mentioned in Telfer's account and the ravine mentioned in local oral history, or that the story has changed over time. While the number 300 may be an exaggeration, considering that there was a sustained period of killing, or that in both versions the victims were trapped in a small space and killed by a well-armed and coordinated group of colonists, the death toll would be high.
According to Milliss there are various versions of the folk tradition of a long campaign covering a large area of Gomeroi country (Milliss, 1992, pp 200-201). One of these is by C.F. Boughton in his serialisation of Moree history in the North West Champion in 1949 and 1951. Broughton wrote, 'I have mentioned the foregoing facts because they give a better understanding of what led up to the Slaughterhouse Creek massacre, that, like the Umbercollie attempt to settle differences, was a reprisal on a larger scale than any other that we have any knowledge of in this district. It was undertaken by district squatters and their stockmen. By the use of slashing whips, and with guns in reserve, the natives were driven into a yard and then shot. From my father, who got the story from those who came to the district before him, I understand that a large number of natives were slaughtered, and in my early boyhood heard men say that bones were still to be seen strewn around the scene of the massacre. My father told us that those guilty were brought to trial, and on some fault in the indictment were acquitted, but on a second trial were found guilty and condemned to death. The creek and the run on which these things occurred now bear the name of Slaughterhouse Creek. The Gwydir Highway crosses this creek about a mile eastward from Biniguy, but the tragedy took place several miles upstream from where the highway crosses the creek' (North West Champion, 20 Oct 1949, p 10).
There are two main locations mentioned in relation to Slaughterhouse Creek where a large amount of people were killed. One is at a stockyard near the junction of Slaughterhouse Creek and the Gwydir River, and the other is at the headwaters of Slaughterhouse Creek in a ravine. The narratives in local 'folk' history (Millis, 1992, pp 198-203) say that there was killing at multiple locations, which accords with the official evidence of a 'war of extermination' and roving bands of armed mounted colonists who would shoot on sight, so it's reasonable to think killing occurred at both these distinct sites, and possibly more. Police Magistrate Day's evidence mentions 'Vinegar Hill'. There is no information available indicating a place of that name in the area. In his notes on p 811, Milliss suggests 'Vinegar Hill' may be Biniguy or 'Binegar'. The word is phonetically similar, so colonists may have, after the massacre, euphemistically corrupted the name to associate it with the Vinegar Hill uprising in the early colony of Sydney, named in turn after a battle in the Irish uprising, or Denny Day or the committee scribe may simply have misheard it as 'Vinegar'.
Edward Mayne estimated the population of Gomeroi people in the area to be 2,000 and 3,000 persons and had seen 700 gathered at a time (Mayne, Evidence to Committee on Police and Gaols 5.9.1839, pp 22-24). These high populations and concentrations indicate a high death toll is reasonable, particularly considering the confined space with little avenue of escape and that the colonists had assembled a large, mounted and well armed force for the purpose of finding and killing Aboriginal people.

In the absence of William Hobbs, the overseer of Myall Creek station on the Gwydir River, twelve horsemen galloped into the station late on Sunday afternoon 10 June 1838 and tied up 28 Wirayaraay old men, women and children and forced them to walk to an area out of sight of the station huts. The horsemen then fired at the tied up people with pistols and fowling pieces and then hacked and bludgeoned them to death with swords and cutlasses. Then they rode off and returned next day and burnt the bodies. The massacre was led by settler John Henry Fleming and eleven stockmen; John Russell, Charles Kilmeister, Edward Foley, Charles Toulouse, James Oates, William Hawkins, John Johnstone, James Parry, John Blake, Edward Palliser and William Lamb. When Hobbs returned to Myall Creek station three days later, he was told about the massacre by hut keeper Charles Anderson and after viewing the burnt bodies, Hobbs wrote a letter reporting the massacre to the Colonial Secretary in Sydney who ordered an investigation by magistrate Edward Denny Day. The ringleader, John Henry Fleming disappeared before Day arrived in the region, leaving the 11 stockmen to take the rap. They were arrested and charged with murder and taken to Sydney for trial in the Supreme Court. However two trials were required before seven of them were convicted and hanged on 18 December 1838. This is the only known case in NSW where perpetrators of a frontier massacre of Aboriginal people were convicted and hanged. Myall Creek is the best known massacre event in Australia. Beginning in 2000, the massacre is acknowledged every June in a public ceremony of remembrance at the massacre site. The ceremony is attended by, among others, descendants of the perpetrators and victims in a gesture of reconciliation. (Based on Lydon and Ryan, 2018).

Following the Myall Creek massacres Commissioner for Crown Lands, Edward Mayne, was sent to the Gwydir River to investigate the status of the region and specifically the earlier killing of shepherds and sheep at Bowman's station, and at Cox's station. While he was there, in August 1838, Charles Eyles, manager at Crawford's station on the Gwydir River and two stockmen, James Dunn and William Allen, shot and killed nine Gomeroi people on Ardgowan Island on the Gwydir River, and burnt and buried the bodies in a shallow grave (Millis, 1992, p 580). The remains were discovered in February 1839 by a trooper under Edward Mayne's command and a drover (Mayne to Colonial Secretary, 23-28 Feb 1839, cited in Milliss 1992, p 580-2). Eyles disappeared along with Dunn while Allen was sent by Mayne to Muswellbrook for interview by magistrate Edward Denny Day who charged him with murder. According to Milliss, Allen was never brought to trial (Milliss 1992, p 678).