Borderline Normal Traditional Cache

It is not often in this wide brown land that the border between two states is a silver metal line embedded in red bricks.  South Australia this side.  Victoria over there.  Stand with one foot in either state and reach for a cache.

South Australia's land borders are defined to the west by the 129° east longitude (129° east) with Western Australia, to the north by the 26th parallel south latitude (26° south) with the Northern Territory and Queensland and to the east by 141° east longitude (141° east) with Queensland, New South Wales and Victoria; however, this is not where all borders are actually marked on the ground.