When Arthur Phillip established his colony at Port Jackson in January 1788 he began exploration at once. In March 1788 he named Pitt Water and in April he explored the northern side of the harbour.
On the 22nd of April 1788, Phillip led a party inland, in search of a large river which he presumed would be found at the "rising of the mountains". The party did not reach the river, but saw, "a country that might be cultivated with ease", and this led to the establishment of the settlement at Rose Hill on the 2nd of November 1788. This was latter named Parramatta.
Phillip's most important discovery during 1789 was the river he named the Hawkesbury, which he found in June when exploring Broken Bay.
Meanwhile, on 26 June 1789 Watkin Tench and a party discovered the Nepean River, which turned out to be the main stream of the Hawkesbury River whose mouth had earlier been discovered by Phillip. To this day the river is still known by both names.
In September 1789 Botany Bay was surveyed to the extent of 48 kilometres and charted by Captain Hunter.
In February 1797 the ship Sydney Cove was wrecked in Bass Strait. Seventeen survivors set out for Port Jackson, and eventually, after considerable hardship, covered about 640 kilometres of coastline on foot. Only three of the men completed that appalling journey, and these were rescued only by chance, about 40 kilometres south of Sydney. They had been walking under the most hazardous conditions for approximately two months.
During the 1790s a number of convicts in New South Wales came to believe that a civilisation existed in an area about 320 kilometres south-west of Sydney, and that they could escape to this place. To disprove this belief, the Governor, Captain John Hunter, sent two expeditions guided by an ex-convict named John Wilson to explore the area. The first party walked approximately 390 kilometres, mainly over very rough country, reaching the junction of the Wingecarribee and Wollondilly rivers. The second party, also on foot, covered about 560 kilometres and penetrated as far as Mount Towrang near the site of the present city of Goulburn. Much hardship was suffered during each journey.
Meanwhile, the Hunter River and the site of Newcastle were discovered by John Shortland in September 1797 while in search of escaped convicts.
George Caley spent a good deal of time in the country beyond Parramatta; he went as far south as the Picton Lakes in 1802 and subsequently explored the country beyond the Nepean River as far as the Warragamba and examined the area now known as Burragorang. In 1807 Caley also explored the country about the Cataract and Cordeaux rivers.