Green’s Dictionary of Slang

(Aus.) a mythical place that is beyond all the bounds of civilization and devoid of any proper comforts.

1896		‘Banjo’ Paterson ‘Hay and hell and Booligal’ (in Bulletin 25 Apr.) n.p.: In fact, the saying far and wide / Along the Riverina side / Is ’Hay and Hell and Booligal’.
1903		Bulletin (Sydney) 19 Nov. 16/1: Cobb and Co.’s Driver (somewhere between Hay, Hell, and Booligal): ‘Did you say, just now, that your station was worth £50,000?’.
1908		C.H.S. Matthews Parson in the Aus. Bush 239: One man is telling you that it is hotter than Hay, and nearly as hot as Booligal.
1936		(con. 1830s–60s) ‘Miles Franklin’ All That Swagger 154: Billy was eager to follow Fullwood to Hell or Hay in order ‘to belt the stuffin’ outer the ole – morepork’.
1986		R. Beckett Dinkum Aussie Dict. 29: Hay, Hell and Booligal: The nasty end of the Back of Beyond. Nowhere, or the fag end of the universe [...] Normally uttered thus: ‘I’m buggered if I know where he’s gone, it’s all Hay, Hell and Booligal here, mate.’.
1995		Bill ‘Swampy’ Marsh Old Yanconian Daze 18: His Mum was the cook on a station somewhere between Hay and Booligal.