[1][7][6] Custon began as a government town which was surveyed in September 1881 and was proclaimed on 8 December 1881.

It was named after the Reverend Percy Cust who married Lucy Caroline Jervois, the second daughter of William Jervois, the then Governor of South Australia.

In 2000, boundaries were declared for the locality which includes the extent of the ceased government town and which was given the “long established name.”[1][3][12][5][4] The Mount Gambier railway line which closed on 12 April 1995 passes through the locality from north to south with the former railway station with the name of Custon being located to the immediate south in the locality of Wolseley.

[1][14] The 2016 Australian census which was conducted in August 2016 reports that Custon had a population of 20 people.

[2] Custon is located within the federal division of Barker, the state electoral district of MacKillop and the local government area of the Tatiara District Council.