The inland desert region of Australia that is otherwise known as the Never-never is also sometimes called the 'Back of Beyond'.
The term is more generally used to refer to any real or imagined remote region. It was first put into print by Sir Walter Scott in his novel The Antiquary, 1816:
"You... whirled them to the back of beyond to look at the auld Roman camp."
The Scots and Irish dialect version 'back o' beyant' is also found in print throughout the 19th century. It's quite possible that Scott anglicised a rural expression rather than coined it himself - something he did numerous times with other phrases.
This spot isn't that remote. In fact, it isn't remote at all. We were doing maintenance on one of our nearby caches and remembered this little tucked away spot. There was a cache nearby years ago, but it is long gone.