District Council of Ridley
It was established on 30 January 1976 with the amalgamation of the District Council of Marne and the District Council of Sedan. It included the whole of the cadastral Hundreds of Bagot, Fisher, Angas, Ridley, Nildottie and Forster, and parts of the Hundreds of Jellicoe and Bowhill. It was divided into four wards: Marne (two councillors), Forster (one councillor), Sedan (three councillors) and Swan Reach (two councillors).
In 1986, it covered an area district of 2300 square kilometres, described as "bounded by Keyneton, Swan Reach, Bowhill and Sanderston". The major service centres were Cambrai, Sedan and Swan Reach, with smaller townships at Black Hill, Bowhill, Keyneton, Nildottie and Purnong. It had a population of 1,740 in 1985, which had marginally declined since the 1960s. The main primary industries in the largely agricultural district were wheat and barley growing and sheep grazing, with irrigated crops along the Murray River, and tourism along the river being of increasing importance.
Chairmen of the District Council of Ridley
- Colin Glen Marks (1976) 
- Hugh William Glastonbury (1976-1978) 
- Colin Glen Marks (1978-1979) 
- Hugh William Glastonbury (1979-1980) 
- John Laurence Schroeder (1980-?) 
- Matthews, Penny (1986), South Australia, the civic record, 1836-1986, Wakefield Press, pp. 510–514, ISBN 978-0-949268-82-2
- "Thursday, January 29, 1976" (PDF). The Government Gazette of South Australia. Government of South Australia. Retrieved 4 December 2016.
- "Thursday, 1 August, 1991" (PDF). The Government Gazette of South Australia. Government of South Australia. Retrieved 22 November 2016.