Silver City Highway is a
Route
The route passes through largely arid terrain, although there are multiple irrigated areas between Buronga and Wentworth in the highway's south. There is relatively flat terrain between Wentworth and Broken Hill that forms arid pastures for grazing. Around Broken Hill and a little to the north the Barrier Range is encountered, which is more hilly than the rest of the route encountered so far, but not mountainous. North of there the country is once again relatively flat, though there are further hills around Milparinka. Near Tibooburra the terrain becomes a stony desert; this kind of terrain is known in Australia as gibber.
Creeks to the north of Broken Hill are generally crossed straight across the riverbed, whether the road has been sealed or not. There is signage to help drivers gauge depth of the waters if there does happen to be flows after rains. The highway also roughly follows the route Charles Sturt took when he explored the area, during his search to find the fabled inland sea.
Wentworth to Broken Hill
left|thumb|200px|Terrain as seen from a [[rest area north of Wentworth]]
Heading north out of Wentworth, the highway enters arid scrublands and it swings northwest towards the Great Darling Anabranch. Once it reaches the normally dry river, it follows the anabranch upstream crossing it at Bunnerungee Bridge. The highway continues to follow the anabranch north, passing nearby several normally dry lakes, including along the shoreline of Popitah Lake. Roughly following the creekbed of Coombah Creek northwards a short distance, the highway then enters the depression of Coombah Lake. The roadway crosses the lakebed atop an embankment. From here the highway re-enters the lakebed and continues along it to its northern extent. To the north of Coombah lake the road passes to the west of similarly dry Kudgee Lake, the roadway then follows the western side of the Pine Creek creekbed crossing it after some distance, then following it along the eastern side much of the remainder of the way Broken Hill. Upon reaching the approaches to Broken Hill, the terrain elevation becomes a little more varied from the very flat journey travelled so far, as this area is part of the Barrier Range. through the Parliament of New South Wales provided for the declaration of Main Roads, roads partially funded by the State government through the Main Roads Board (MRB). Main Road No. 69 was declared along this road on 8 August 1928, from Wentworth via Broken Hill, Milparinka and Tibooburra to the state border with Queensland; to provide for additional declarations of State Highways and Trunk Roads, this was amended to Trunk Road 69 on 8 April 1929.
The Department of Main Roads, which had succeeded the New South Wales MRB in 1932, declared State Highway 21 on 16 March 1938, from Cobham Lake via Milparkinka and Tibooburra to the state border with Queensland at Olive Downs (and continuing south via White Cliffs, Wilcannia, Booligal, Hay and Deniliquin to the state border with Victoria at Moama); Trunk Road 69 was truncated to meet State Highway 21 as a result. State Highway 22 was later declared on 24 January 1945, from the intersection with Sturt Highway at Buronga via Wentworth, Broken Hill, Cobham Lake, Milparkinka and Tibooburra to the state border with Queensland at Olive Downs, subsuming Trunk Road 69; with a branch to Abbotsford Bridge over the Murray River at Curlwaa also declared, through the Parliament of New South Wales updated road classifications and the way they could be declared within New South Wales. Under this Act, Silver City Highway today retains its declaration as Highway 22, from the intersection with Sturt Highway at Buronga via Wentworth, Broken Hill, Cobham Lake and Tibooburra to the state border with Queensland at Warri Gate, with a branch to Abbotsford Bridge over the Murray River at Curlwaa.
Silver City Highway was signed National Route 79 between Broken Hill and Curlwaa, and the branch to Curlwaa to Abbotsford Bridge and Calder Highway, in 1955. With the conversion to the newer alphanumeric system in 2013, this was replaced with route B79 between Broken Hill and Buronga; the branch from Curlwaa to Abbotsford Bridge is now unallocated, despite route A79 continuing along Calder Highway in Victoria. The highway north of Broken Hill also remains unallocated.
Sealing
The Wentworth to Broken Hill section was sealed in 1969.
Work began in 2011 to seal the remaining 150 km of unsealed highway. In June 2018, the NSW Government announced it was investing $145 million to seal the remaining 209 km of the Cobb and Silver City Highways by 2023. By July 2020 the highway was sealed as far as Tibooburra, and by December 2022, the entire length to the Queensland border was sealed.