The name Eureka originates from site of the Eureka Rebellion. Considered by many as the birth of democracy in Australia, it was here that rebel miners first flew the Eureka Flag. Now, Eureka is home to the Eureka Stockade Gardens and the Eureka Centre, home of the Eureka Flag.

The electorate of Eureka is a mixed rural-urban seat covering the area to the west of Melton, northwest of Geelong, and east of Ballarat. The electorate covers the southern parts of the Ballarat metropolitan area to Canadian, Ballarat East and other suburbs, and most of the Moorabool Shire and Golden Plains Shire.

The Eureka electorate is made up of Bacchus Marsh, Ballan, Brown Hill, Bungaree, Buninyong, Canadian, Clarendon, Darley, Elaine, Eureka, Gordon, Inverleigh, Lethbridge, Maddingley, Meredith, Mount Clear, Mount Egerton, Mount Pleasant, Rokewood, Shelford, Teesdale, and Warrenheip. The electorate covers 3,915 square kilometres.