Named after explorer Ernest Giles, it is the largest electorate in the state by area, covering 497,005 km2 (191,895 sq mi) of South Australian outback.

Its main population centre is the industrial city of Whyalla on the far south-east border of the seat which represents half of the electorate's voters.

The electorate covers significant areas of pastoral leases and Pitjantjatjara Aboriginal land stretching to the Western Australian and Northern Territory borders, taking in the remote towns of Andamooka, Coober Pedy, Ernabella, Fregon, Marla, Mimili, Mintabie, Oodnadatta, and Tarcoola.

Sitting Labor MP for Whyalla and incumbent government minister Frank Blevins had won a second term in 1989 with a safe 10.9 percent two-party preferred margin.

At this election Blevins retired, and his successor, Lyn Breuer, picked up a swing large enough to make Giles a safe Labor seat.