Mulgoa takes its name from the Mulgoa people who were the indigenous inhabitants of the area and spoke the Dharug language. The name is believed to mean black swan. The Mulgoa weren't the only inhabitants of the area. They shared the Mulgoa Valley with the Gandangara people of the Southern Highlands, whose territory extended up into the Blue Mountains. They lived a hunter-gatherer lifestyle governed by traditional laws, which had their origins in the Dreamtime. Their homes were bark huts called 'gunyahs'. They hunted kangaroos and emus for meat, and gathered yams, berries and other native plants.

Following the arrival of the First Fleet in Sydney, there were a number of bloody battles between the British settlers and the local indigenous people in this area, however, it is believed that the Mulgoa people were generally peaceful and most of the clashes were with the Gandangara. The first government land grants in the area were made in 1810 to Edward Cox, the four-year-old son of Captain William Cox, who constructed a famous road across the Blue Mountains in 1814. William Cox built The Cottage on the land in about 1811. Not far away dwelt Cox's friend Sir John Jamison, who erected the colony's finest mansion, Regentville House, in 1824, on an eminence overlooking the Nepean River. In 1821, three large land grants were made on the Nepean at Mulgoa to the Norton family: James Norton, the founder of Sydney's first law firm and his father and brother, Nathaniel.

...
Wikipedia