Before Federation knitted the Australian colonies together in 1901, the lines between them were real economic borders, walled by tariffs and watched by customs men. Birdsville - first known as Diamantina Crossing, sitting at a permanent waterhole on the stock route between Queensland and South Australia - became one of fourteen pre-Federation border posts. Duties were levied on cattle and goods crossing into the colony, and that money needed an officialdom to collect it and courts to enforce it. The township was gazetted in 1885; the courthouse and its police complex followed by 1890, built of local stone cut in blocks because there was almost no timber to be had. It survives as one of only three masonry buildings left from old Birdsville, alongside the Birdsville Hotel and the former Royal Hotel.

Policing a beat the size of a small country demanded unusual transport, and in 1886 camels arrived in Birdsville to do the work horses could not. The first six came from India in poor condition - only four survived the early months - but the survivors proved their worth, carrying officers hundreds of kilometres to collect statistical returns and chase reports across waterless country. One tracker was given charge of the station's camels. The image is worth holding onto: in the 1890s, the long arm of Queensland law in this district reached out at the swaying pace of a camel, across gibber and dune, between station and waterhole, in heat that could kill the unprepared.

The police complex's most skilled members were Aboriginal trackers, and their record here is long and remarkable. An Aboriginal tracker was stationed with the first contingent of officers in 1884, and two men in particular gave the institution its continuity. Tracker Billy served from 1885 to 1905; Corporal Tommy served from 1905 to 1952 - nearly half a century reading country that white officers could not. These men possessed an intimate knowledge of land that was, in many cases, their own people's country - the lands of the Wangkangurru and Yarluyandi - and the colonial system depended on their expertise even as it offered them little in return. A separate tracker's hut once stood at the rear of the station; a storm destroyed it in 1985. The complex that remains is, in part, a memorial to their work.

What stands today has changed little in shape: an L-shaped stone building with the courtroom in one wing, its bench at the rear, wrapped on three sides by verandahs since enclosed against the heat. A modern police station opened next door in 1988, but the old courthouse never quite retired. For years it served as overflow accommodation during the Birdsville Races, when the town's single hotel could not hold the crowds and extra police were posted in to keep order. In one delightfully outback footnote, scientists from Nagoya University in Japan were granted permission in 1995 to install recording equipment in the surviving lockup. Frontier justice, then a guest room, then a laboratory - all in one small stone building that the desert twice tried, and twice failed, to bring down.