Sir Augustus Charles Gregory (1 August 1819 - 25 June 1905) was an Australian explorer who in the 1840s and 1850s helped chart inland Western Australia.

He was born at Farnsfield , Nottingham, England, the son of Joshua Gregory and his wife, Frances Churchman. Gregory was educated privately and was taken by his parents to Western Australia in 1829.

In 1841 he entered the government survey office, and in 1846, with his two brothers, F. T. Gregory and H. C. Gregory, made his first exploration. With four horses and seven weeks' provisions they left T. N. Yule's station 60 miles northeast of Perth, Australia on 7 August 1846 and explored a considerable amount of the country to the north of Perth, returning after an absence of 47 days during which they had covered 953 miles (1534 km).

Two years later, Gregory took command of another expedition to examine the course of the Gascoyne River , and especially to look for new pasture-land. The party left on 2 September 1848, crossing the Murchison River 25 September, but the country was very dry it became difficult to water the horses. Gregory decided to turn south again in the beginning of October, and on 6 October decided to rest the horses by the Murchison River. The party returned to Perth on 12 November after having sucessfully finding good pastureland. In spite of water difficulties about 1500 miles (2414 KM) were covered in a period of 10 weeks.

In 1854 Gregory was asked to lead an expedition to the interior. Gregory had his brother, H. C. Gregory, as second in command and Baron von Mueller as botanist. There were 18 men altogether, with 50 horses and 200 sheep. The party left Moreton Bay by sea on 12 August 1855, and Port Essington was sighted on 1 September. On the next day their vessel grounded on a reef and it was impossible to float off until 10 September. At the end of the month the party split up, with one group going up the river in a schooner, while Gregory led the other over the range. They were not reunited until 20 October. They reached Brisbane on 16 December 1856 after having surveyed an extensive swath of land.

In September 1857 Gregory was asked by the government of New South Wales to search for traces of Ludwig Leichhardt, a fellow explorer who had disappeared on an earlier expedition. A party of nine was formed with Gregory in command and his brother, C. F. Gregory, as second in command. On 24 March 1858 the expedition left Juandah . On 21 April a tree marked with an L was found in latitude 24 degrees 35 min. and longitude 146 degrees 6 min. The Barcoo River was then followed to its junction with the Thompson River. On 15 May the country was so dry the expedition turned south to save the horses. Cooper's Creek was followed until it was close to the South Australian border, coming to Strzelecki Creek on 14 June. Continuing his course mostly to the south, on 26 June he decided to proceed to Adelaide, which was reached at the end of July 1858.

Gregory did no further exploring but was appointed surveyor-general of Queensland in 1859 and held the position until 1879 when he retired. In 1882 he was made a member of the legislative council and continued to be a member until his death. He was interested in scientific research and was a trustee of the Queensland Museum . He was awarded the gold medal of the Royal Geographical Society in 1858 and was knighted in 1903. With his brother, F. T. Gregory, he published their Journals of Australian Exploration in 1884. He died unmarried.

Reference

• Public Domain text from the Dictionary of Australian Biography, by Percival Serle , 1949. [1]