The route of the Barrier Highway was proclaimed as State Highway No. 8 on 7 th August 1928, but it was not until 1959 that the highway was named “Barrier Highway” after the Barrier Range, from which ore is mined at Broken Hill.

The highway can trace its origins to the mail coaches serving remote mining outposts in the 1880s. A road was surveyed from Nyngan to Wilcannia along the tracks used by mailmen in 1884 and by 1889 a road existed between Wilcannia and Silverton. This road was later altered to pass through Broken Hill and Thackaringa en route to the South Australian border at Cockburn.

Despite being proclaimed a State Highway in 1928, it was not until 2 September 1935 that the Department of Main Roads assumed control of the Barrier Highway. Prior to this, the Department of Public Works had responsibility for all works in the unincorporated area.

By 1953, when the comprehensive reconstruction and sealing programme was begun, the only sealed sections of the Barrier Highway were located in the towns of Cobar and Broken Hill. Outside of the towns, the road pavement consisted largely of the natural material through which the road formation passed and only very clayey or sandy sections were stabilised with gravel or sand clay. Bridges and culverts were few and far between and most large watercourses were crossed by gravelled causeways.

When the time came for reconstruction of the highway its location was reviewed throughout with the aid of aerial photos. Although many sections were relocated to avoid low-lying ground, only one major deviation was required, a 39 mile (63km) deviation across Maccullochs Range. Construction of this deviation marked the completion of the reconstruction programme.

Reconstruction work commenced with the 49km section between Broken Hill and Cockburn, as it had the highest traffic volumes, and this work was completed by 1955. Between Nyngan and Cobar, a distance of 131km, the bituminous sealing was completed in November 1969. During this time, the bitumen was also being extended easterly from Broken Hill and westerly from Cobar. The bitumen reached Wilcannia from the west in November 1970 and by this stage the bitumen had been substantially completed between Wilcannia and Cobar – only the deviation across the Maccullochs Range remained.

Ironically, the Barrier Highway crosses one of the driest areas in New South Wales, yet drainage facilities – including over 100 bridges and 47,000 linear feet of culverts – formed a major part of the work. This is due to the occasional heavy downpours which cause sudden flooding of many undisciplined watercourses across the plains. The extensive culvert and bridge construction was aimed at reducing to an absolute minimum the time the highway could be closed during a flood as well as preventing serious damage, such as scouring, to the road surface and formation.

At the Maccullochs Range, which is the only vertical feature over hundreds of miles of central western plains, a 63km deviation was constructed. The original route skirted the northern extremity of the range and passed through a number of low-lying areas, which become a series of shallow lakes after rain. To eliminate the problem of flooding from the highway, a new route running along the range was chosen and this new route has the added bonus of shortening the length of the highway by 3km. The deviation cost $2.5 million of the total sum of $16 million that was spent on the highway since 1953.

On the 31 st of October 1972, the remaining hundred metres of seal was placed before a large audience. The Minister for Highways, C. B. Cutler, made the symbolic ‘final fling’, placing the last few shovels of aggregate onto the roadway to signify the completion of the Barrier Highway.

Since then, only a few major projects have been undertaken on the Barrier Highway. A 6km realignment of the highway through the Thackaringa Hills (32.6-38.5km west of Broken Hill), completed in January 1989, improved a section of highway that had remained largely unchanged since the turn of the century, other than having been sealed with bitumen in 1953-55. East of Broken Hill, the approach to town was improved by the Mt Darling Creek Deviation, which was completed in May 1991. Further east, the Barrier Highway turns south from Wilcannia towards the Cobb Highway junction, and this 19km section crosses two major flood plains. The ageing timber bridges, which had been constructed in the late 19th century, across Talyawalka Creek, the Darling River and the flood channels were all replaced. The new crossing of Talyawalka Creek and floodplain was opened to traffic in October 1983, but it was not until December 1991 that new bridges over the Darling River and floodplain were completed. The old bridge over the Darling River was a steel truss bridge with a bascule lift span, built in 1895 when steamers still regularly plied the river. The old bridge has been retained and lies only metres downstream from the present bridge.

The Roads and Traffic Authority has not released plans for any further improvement of the Barrier Highway.