The Register, originally the South Australian Gazette and Colonial Register, and later South Australian Register, was South Australia's first newspaper. It was first published in London in June 1836, moved to Adelaide in 1837, and folded into The Advertiser almost a century later in February 1931.
The newspaper was the sole primary source for almost all information about the settlement and early history of South Australia. It documented shipping schedules, legal history and court records at a time when official records were not kept.  According to the National Library of Australia, its pages contain "one hundred years of births, deaths, marriages, crime, building history, the establishment of towns and businesses, political and social comment". 
All issues are freely available online, via Trove.
This article needs additional citations for verification .(February 2019)
The Register was conceived by Robert Thomas, a law stationer, who had purchased for his family 134 acres (54 ha) of land in the proposed South Australian province after being impressed by the ideas of Edward Gibbon Wakefield.  The first issue (printed by William Clowes & Sons, Duke-street, Stamford-street, Lambeth, London),  appeared in London on 18 June 1836 with his friend and partner, George Stevenson, as editor. Thomas embarked for South Australia aboard the Africaine later that year, arriving on 10 November 1836 with his family and equipment to set up a printing plant.  It was six months before the first colonial edition of The Register was printed on 3 June 1837 in a small mud hut on Town Acre No. 56  in Hindley Street, near what is now named Register Place. (The colloquialism "mud hut" would seem to be an understatement for a substantial pisé building in which was operated a demy Stanhope press, an ancient wooden press, and racks holding "half a ton of bourgeois and brevier type, a good fount of small pica for printing official documents, and a quantity of general jobbing type"  with all the other requirements for editing, setting up, printing and distributing an admittedly small circulation newspaper.)
From the start, the paper asserted a strongly independent stance.  Stevenson's style was vigorous and provocative, making himself and The Register several enemies.  His opposition to Colonel William Light's choice of site for the new capital and J.H. Fisher as Resident Commissioner, led them and others to found the Southern Australian in direct competition with The Register.  The paper's antagonism of Governor Gawler led to The Register losing government business notably the South Australian Government Gazette . The printers Thomas & Co. had disengaged themselves from editorial content in June 1839 in a vain attempt to protect their monopoly  and lost about £1,650 a year.  His protest that he was authorised by the British Government to do its printing failed and, insolvent, he sold the paper for £600 to James Allen (previously editor of the South Australian Magazine)  in 1842, as Stevenson withdrew from journalism.
Thomas also published the weekly Adelaide Chronicle and South Australian Literary Record (10 December 1839 – 18 May 1842).
John Stephens, who had in 1843 founded The Adelaide Observer , in 1845 purchased The Register.  Anthony Forster became part owner in 1848; With the death of Stephens in 1850, his share was taken over by John Taylor.  Forster's share was taken over by Joseph Fisher in 1853, then sold to John Howard Clark in 1865. 
The paper, having been printed sporadically previously, became weekly in June 1838 and later twice-weekly from February 1843. By 1840, The Register employed a staff of 21. These were an editor, three pressmen, ten compositors, two binders, a collector, a clerk, delivery man and two boys. One of its compositors also acted as sub-editor.  Its circulation by 1840 was 900.
On 1 January 1850, it became a daily publication, and three years later the paper was bought back by Thomas's son William Kyffin Thomas as part of South Australia's first media syndicate with Anthony Forster, Edward William Andrews and Joseph Fisher.  They also purchased its weekly sister publication, The Adelaide Observer, and established The Evening Journal (January 1869 – September 1912) which morphed into The Journal (October 1912 – July 1923) which then became The News . Its Saturday edition was called The Saturday Journal (July 1923 – April 1929).
The Register outlasted many competitors throughout its long history, holding a monopoly on the market at various stages, but it ultimately met its match in The Advertiser . The Advertiser, founded in 1858, first emerged as a serious challenger to the paper in the 1870s. The defining move which swung Adelaide readership from the conservative Register to the more egalitarian Advertiser was the latter's dramatic price reduction from 2d. to 1d., and hiring an army of canvassers, on commission, to peddle the paper. The Register was slow to respond, the Advertiser started putting its circulation figures on the masthead. By the time the Register cut its price the die was cast.  The Advertiser bought out The Register and closed it down in February 1931 after the Great Depression had severely reduced its fortunes, forcing it to become largely pictorial. 
Details are from an article marking the 50th anniversary of its first publication in South Australia  and from 1886 the article "Sketch of the History of the Register"  except where noted.
The Advertiser is a daily tabloid format newspaper based in the city of Adelaide, South Australia. First published as a broadsheet named The South Australian Advertiser on 12 July 1858, it is currently a tabloid printed from Monday to Saturday. The Advertiser came under the ownership of Keith Murdoch in the 1950s, and the full ownership of Rupert Murdoch in 1987. It is a publication of Advertiser Newspapers Pty Ltd (ADV), a subsidiary of News Corp Australia, itself a subsidiary of News Corp. Through much of the 20th century, The Advertiser was Adelaide's morning broadsheet, The News the afternoon tabloid, with The Sunday Mail covering weekend sport, and Messenger Newspapers community news. The head office was relocated from a former premises in King William Street, to a new News Corp office complex, known as Keith Murdoch House at 31 Waymouth Street.
The South Australian Company, also referred to as the South Australia Company, was formed in London on 9 October 1835, after the South Australia (Foundation) Act 1834 had established the new British Province of South Australia, with the South Australian Colonization Commission set up to oversee implementation of the Act.
The Adelaide Club is an exclusive gentlemen's club situated on North Terrace in the South Australian capital city of Adelaide. Founded in 1863, the club comprises members of the Adelaide Establishment.
George Stevenson was a pioneer South Australian newspaper editor and horticulturist. He came to Adelaide as private secretary to the first Governor of South Australia, John Hindmarsh.
Robert Thomas was a Welsh newspaper proprietor, printer and early settler of South Australia who was born on a farm 'Rhantregynwen', at Llanymynech, Powys, Wales.
Sir Robert Kyffin Thomas was a South Australian newspaper proprietor.
John Howard Clark was editor of The South Australian Register from 1870 to 1877 and was responsible for its Echoes from the Bush column and closely associated with its Geoffry Crabthorn persona.
The South Australian was a newspaper published in Adelaide, the capital of colonial South Australia from 2 June 1838 to 19 August 1851. Between 1838 and 1844, it was published as The Southern Australian.
John Stephens was a writer, polemicist and editor in England who became an editor and newspaper owner in the early days of South Australia.
The Herald was a weekly trade union magazine published in Adelaide, South Australia between 1894 and March 1910; for the first four years titled The Weekly Herald. It was succeeded by The Daily Herald, which ran from 7 March 1910 to 16 June 1924.
William Kyffin Thomas was a newspaper proprietor in South Australia. William, the son of Robert Thomas, was born in Fleet Street, London and emigrated to South Australia with his father in 1836 on the Africaine. From that time until the day of his death, he was intimately associated with the fortunes of the South Australian Register, for the last twenty-five years of his life as one of the proprietors. To his industry and ability in the different capacities in which he acted was due to a large extent the high character and phenomenal success of the Register, and the weekly and afternoon journals issued from the same office—the Adelaide Observer and Evening Journal. The firm which conducted these papers bore the name of the subject, being known as W. K. Thomas & Co., and consisted of John Harvey Finlayson and Robert Kyffin Thomas, the latter being the elder son of William Kyffin Thomas, and grandson of the founder of the Register.
The Southern Cross is the official publication of the Catholic Archdiocese of Adelaide. About 5000 copies are printed monthly and distributed to parishes, schools and agencies, besides an online version. It began in July 1889 as a weekly magazine published in Adelaide, South Australia, for the Catholic Archdiocese of Adelaide, and remained a weekly for most of its history. Its banner was subtitled A weekly record of Catholic, Irish and General Intelligence, and later Organ of the Catholic Church in South Australia. The current, non-print website version of the magazine also bears the name Southern Cross.
Andrew Murray (1813–1880) was an Australian journalist.
Quiz was a weekly newspaper published in Adelaide, South Australia from 1889 to 1910. Between 1890 and 1900 it was known as Quiz and The Lantern.
Charles Birks & Co Ltd. was a South Australian department store founded by Charles Napier Birks in Rundle Street, Adelaide. His son Napier Birks took over the business in 1908. The business was acquired by David Jones Limited in 1954.
The Port Adelaide News was a newspaper published in Port Adelaide, South Australia between 1876 and 1933 with various sub-titles, several breaks in publication and periods of bi-weekly publication.
The Kapunda Herald was a newspaper published in Kapunda, South Australia from 29 October 1864 to 25 January 1951. From 1864 to 1878 the masthead was subtitled "and Northern Intelligencer". It was published weekly, except for the period February 1872 to September 1894 when it appeared bi-weekly. When closed, the newspaper was merged with the Barossa News to become the Barossa and Light Herald.
Samuel Edward Roberts was a printer and publisher in Adelaide.
The Adelaide Chronicle was an early publication in Adelaide, the capital of the then colony of South Australia. It was published between 1839 and 1842, when it ceased publication as a result of the economic depression caused by the mass exodus of workers to the Victorian goldfields.
Henry Hussey was a pastor in the colonial days of South Australia, closely associated with the Christian Church on Bentham Street along with pastors Abbott, Finlayson and Playford. He was the author of several influential books on religious themes, and a memoir.