# List of road routes in South Australia

Road routes in South Australia assist drivers navigating roads in urban, rural, and scenic areas of the state. Today, all numbered routes in the state are allocated a letter (M, A or B) in addition to a one, two or three digit number, denoting different levels of significance. The route system includes officially designated highways, urban freeways and arterial roads, and other important cross-state roads that have not been declared highways.

## History

Route numbers have been allocated to South Australia's roads since 1955, with the introduction of National Routes across all states and territories in Australia, symbolised by a white shield with black writing; National Route 1 ('Highway 1') was one of the best-known numbered national routes, due to its fame for circumnavigating the continent.
In 1974, the National Highway network was defined, which allowed some existing National Routes to be upgraded to National Highways. These were marked with the same shield design as the National Routes, except for their gold-on-green colouring and the word NATIONAL added across the top. Unlike many other states, South Australia never adopted State Routes, although it allowed two Victorian rural State Routes to cross the border and terminate in locations within 20 km of it when they were rolled out there in 1985.
In 1998, the state replaced its system of National Routes and National Highways with an alphanumeric route numbering system. Many existing numbered routes were allocated a letter (M, A or B) in addition to its number, with 'M' routes denoting freeways, 'A' routes denoting routes of state significance, and 'B' routes denoting routes of local significance. Instead of shields, route numbers are displayed as yellow text on green rectangular backgrounds, and has now become the sole route numbering system in the state. The changeover to alphanumeric routes was carried out from 1998 either by removing old "shield" coverplates installed on newer signs, or installing new alphanumeric coverplates on old shielded signs, adopting the same design as Victoria (which adopted its alphanumeric system a year previous). Trailblazers were introduced with alphanumeric routes in Adelaide's metropolitan area and the tourist areas of Victor Harbor and the Barossa Valley in 1998, with allocations extended to cover country areas in 1999. Former National Highways still retained their shield design (including NATIONAL markings) after conversion, but were modified in 2017 to remove them, bringing their design in line with the rest of the state.

## Alphanumeric Routes

All alphanumeric routes listed here are derived from the Government of South Australia's Location SA service.

### M routes

Roads allocated an M route are usually at least dual-carriageway motorways or expressways, with at least two lanes in each direction. These roads keep traffic moving and are likely to have no traffic lights and higher speed limits.
| Route | Component roads | From | Via | To | Length | Notes |
| M1 | South Eastern Freeway | Glen Osmond | Stirling Mount Barker Callington | Murray Bridge | 69 km (43 mi) | Part of Highway 1: – western end re-aligned through Eagle on the Hill from Mount Barker Road to current alignment when freeway extension through the Heysen Tunnels opened in 2000 – continues north west as along Glen Osmond Road beyond Adelaide – continues east as along Princes Highway to Tailem Bend – allocated in 1998, progressively being replaced by from 2017 |
| M2 | Northern Expressway | Gawler | Angle Vale Waterloo Corner Wingfield | Hindmarsh | 51 km (32 mi) | Allocated in 2016 (replacing ) |
| M2 | Northern Connector | Gawler | Angle Vale Waterloo Corner Wingfield | Hindmarsh | 51 km (32 mi) | Allocated upon opening in 2020 |
| M2 | North–South Motorway | Gawler | Angle Vale Waterloo Corner Wingfield | Hindmarsh | 51 km (32 mi) | – allocated through Wingfield (replacing ) when South Road Superway opened in 2014, progressively being replaced by from 2017 – extended south to Hindmarsh (replacing ) when Torrens to Torrens section opened in 2018 – to be extended further south eventually to Southern Expressway as further stages of the North–South Motorway are completed – continues south as along South Road to Southern Expressway at St Marys |
| M2 | Southern Expressway | St Marys | Darlington Reynella | Noarlunga Downs | 21 km (13 mi) | – southern end extended from Reynella to Noarlunga Downs when second stage opened in 2001 – northern end extended from Darlington to St Marys when Darlington bypass opened in 2020 – to be extended further north eventually to North–South Motorway as further stages are completed – continues north as along South Road to North–South Motorway at Hindmarsh |
| National Highway M20 | Northern Expressway | Virginia | Munno Para West Angle Vale | Gawler | 22 km (14 mi) | Allocated upon opening in 2010, replaced by when Northern Connector commenced construction in 2016 |
| Decommissioned or unsigned route |||||||

### A routes

Roads allocated an A route are main or arterial routes providing a high standard of driving conditions both across single- or dual-carriageway roads, linking to and from M roads and provide access to major towns and places of interest across metro and regional SA.
| Route | Component roads | From | Via | To | Length | Notes |
| A1 | Eyre Highway Augusta Highway Port Wakefield Highway Port Wakefield Road Main North Road | SA/WA border | Ceduna Kyancutta Kimba Port Augusta Snowtown Port Wakefield Gepps Cross | Medindie | 1,248 km (775 mi) | Part of Highway 1: – continues west as along Eyre Highway into WA eventually to Norseman – discontinuous across the Adelaide city centre, partially – allocated in 1998, progressively being replaced by from 2017 |
| A1 | Fullarton Road Glen Osmond Road | Eastwood | Frewville | Glen Osmond | 3.3 km (2 mi) | – discontinuous across the Adelaide city centre, partially – eastern end along Mount Barker Road terminating in Crafers truncated to current alignment when South Eastern Freeway extension through the Heysen Tunnels opened in 2000 – continues east as along South Eastern Freeway to Murray Bridge – allocated in 1998, progressively being replaced by from 2017 |
| A1 | Princes Highway | Murray Bridge | Swanport Bridge | Tailem Bend | 22 km (14 mi) | – continues west as along South Eastern Freeway to Glen Osmond – continues south as along Princes Highway to Mount Gambier – allocated in 1998, progressively being replaced by from 2017 |
| A1 | Princes Highway | Mount Gambier | | SA/Vic border | 18 km (11 mi) | – continues west as along Princes Highway to Tailem Bend – continues east as along Princes Highway into Victoria eventually to Geelong |
| A2 | South Road | Hindmarsh | Mile End Edwardstown | St Marys | 11 km (7 mi) | – allocated from Regency Park to Darlington (replacing ) when South Road Superway opened in 2014 – northern end truncated to Hindmarsh (replaced by ) when Torrens to Torrens section of North–South Motorway opened in 2018 – southern end truncated to St Marys (replaced by ) when Darlington bypass of Southern Expressway opened in 2020 – continues north as along North–South Motorway to Gawler – continues south as along Southern Expressway to Noarlunga Downs |
| A3 | Cross Road | Plympton | Unley Park | Glen Osmond | 9.5 km (6 mi) | |
| A5 | Anzac Highway | Keswick | Plympton | Glenelg | 13.8 km (9 mi) | Northern end truncated from Adelaide to Keswick when City Ring Route re-aligned in 2017 |
| A6 | Sir Donald Bradman Drive Burbridge Road | Mile End | Brooklyn Park | West Beach | 6.9 km (4 mi) | Eastern end truncated from Adelaide to Mile End when City Ring Route re-aligned in 2017 |
| A7 | Port Road Commercial Road | Hindmarsh | West Croydon Woodville South Cheltenham | Port Adelaide | 9.9 km (6 mi) | |
| A8 | Dukes Highway | Tailem Bend | Coonalpyn Tintinara Keith Bordertown | SA/Vic border | 192 km (119 mi) | – continues east as along Western Highway into Victoria eventually to Beaufort – concurrency with along Dukes Highway from Lowan Vale to Bordertown – allocated in 1998, progressively being replaced by from 2017 |
| A9 | Port River Expressway Salisbury Highway John Rice Avenue | Port Adelaide | Mawson Lakes Salisbury | Elizabeth Vale | 20.9 km (13 mi) | Eastern end extended along Salisbury Highway and John Rice Avenue from Dry Creek to Elizabeth Vale (replacing /) when South Road Superway opened in 2014 |
| A10 | Northcote Terrace North East Road | Gilberton | Greenacres Modbury | Houghton | 19.3 km (12 mi) | Continues east as along North East Road to Nurioopta |
| A11 | North Terrace Payneham Road Lower North East Road Hancock Road Yatala Vale Road The Grove Way | Kent Town | Marden Campbelltown Hope Valley Tea Tree Gully Golden Grove | Salisbury Heights | 25.1 km (16 mi) | Northern end re-aligned from Lower North East Road terminating in Houghton (replaced by ) to current alignment in 2021 |
| A13 | Main South Road Victor Harbor Road | Darlington | Old Reynella Old Noarlunga Willunga | Victor Harbor | 67.6 km (42 mi) | – allocation along South Road, Salisbury Highway and John Rice Avenue terminating in Elizabeth Vale truncated to current alignment (replaced by / and ) when South Road Superway opened in 2014 – concurrency with along Victor Harbor Road through Willunga Hill – allocated along South Road through Wingfield in 1998, replaced by in 2014, progressively being replaced by from 2017 |
| A14 | East Avenue Holbrooks Road Marion Road | Beverley | Brooklyn Park Plympton | Darlington | 15.3 km (10 mi) | |
| A15 | Tapleys Hill Road Brighton Road Ocean Boulevard Lonsdale Road Dyson Road Murray Road Gawler Street | Alberton | Seaton Glenelg Brighton Hallett Cove Seaford Port Noarlunga | Maslin Beach | 45.3 km (28 mi) | |
| A15 | Gray Street Saltfleet Street Commercial Road Maslin Beach Road | Alberton | Seaton Glenelg Brighton Hallett Cove Seaford Port Noarlunga | Maslin Beach | 45.3 km (28 mi) | Southern end extended from Hallett Cove to Maslin Beach in 2021 |
| A16 | Oliver Rogers Road Victoria Road Nelson Street Semaphore Road Causeway Road Bower Road | Outer Harbor | Port Adelaide Mansfield Park Gepps Cross Hope Valley | Houghton | 37.5 km (23 mi) | |
| A16 | Grand Junction Road | Outer Harbor | Port Adelaide Mansfield Park Gepps Cross Hope Valley | Houghton | 37.5 km (23 mi) | Allocated (from Regency Park to Northfield) in 1998, progressively being replaced by from 2017 |
| A16 | Lower North East Road | Outer Harbor | Port Adelaide Mansfield Park Gepps Cross Hope Valley | Houghton | 37.5 km (23 mi) | Eastern end extended along Lower North East Road from Hope Valley to Houghton (replacing ) in 2021 |
| A17 | Hampstead Road Taunton Road Ascot Avenue Lower Portrush Road Portrush Road | Northfield | Payneham | Glen Osmond | 13.7 km (9 mi) | Allocated in 1998, progressively being replaced by from 2017 |
| A18 | Bolivar Road Kings Road McIntyre Road | Paralowie | Parafield | Modbury | 12.5 km (8 mi) | |
| A20 | Main North Road Gawler Bypass Sturt Highway | Gepps Cross | Elizabeth Gawler Nurioopta Waikerie Barmera Renmark | SA/Vic border | 267 km (166 mi) | – continues east as along Sturt Highway into Victoria through Mildura, and into New South Wales eventually to Tarcutta – allocated in 1998, progressively being replaced by from 2017 – western end along Main North Road terminating at Gepps Cross truncated to Gawler (replaced by ) when Northern Expressway opened in 2010, reverted to in 2017 |
| A21 | Port Road Park Terrace Fitzroy Terrace Robe Terrace Park Road (s/bound) Mann Road (n/bound) Hackney Road Dequetteville Terrace Fullarton Road Greenhill Road Goodwood Road West Terrace | Adelaide | North Adelaide | Adelaide | 15.6 km (10 mi) | Former City Ring Route, replaced by in 2017, listed clockwise from the western corner of Adelaide city centre |
| A22 | Cavan Road Churchill Road Torrens Road | Gepps Cross | Kilburn | Ovingham | 7.7 km (5 mi) | |
| A32 | Barrier Highway | Giles Corner | Saddleworth Burra Ucolta | SA/NSW border | 377 km (234 mi) | – continues east as along Barrier Highway into New South Wales to Nyngan – concurrency with along Barrier Highway through Burra |
| A52 | Main North Road | Gepps Cross | Elizabeth Salisbury | Gawler | 32 km (20 mi) | Allocated when Northern Expressway opened (replacing ) in 2010, reverted to in 2017 |
| A66 | Riddoch Highway | Keith | Padthaway Naracoorte Penola Tarpeena | Mount Gambier | 210 km (130 mi) | Continues south as along Riddoch Highway to Port MacDonnell |
| A87 | Stuart Highway | SA/NT border | Marla Coober Pedy Pimba | Port Augusta West | 928 km (577 mi) | – continues north as along Stuart Highway into NT eventually to Daly Waters – allocated in 1998, progressively being replaced by from 2017 |
| Decommissioned or unsigned route |||||||

### B routes

Roads allocated a B route are secondary or local arterial roads, These roads link to and from A and M roads and provide access to places of interest across metro and regional SA.
| Route | Component roads | From | Via | To | Length | Notes |
| B1 | Princes Highway | Tailem Bend | Meningie Kingston SE Millicent | Mount Gambier | 350 km (217 mi) | Part of Highway 1: – continues north as along Princes Highway to Murray Bridge – continues east as along Princes Highway into Victoria eventually to Geelong |
| B10 | North East Road Torrens Valley Road Eden Valley Road Angaston Road | Houghton | Birdwood Mount Pleasant Angaston | Nurioopta | 73 km (45 mi) | – continues west as along North East Road to Adelaide – concurrencies with: along North East Road through Chain of Ponds; along Torrens Valley Road through Birdwood; along Torrens Valley Road through Mount Pleasant |
| B12 | Mallee Highway | Tailem Bend | Lameroo Pinnaroo | SA/Vic border | 145 km (90 mi) | – continues east as along Mallee Highway into Victoria eventually to Piangil – concurrency with along Mallee Highway through Pinnaroo |
| B19 | Main North Road Barossa Valley Way | Gawler | Lyndoch | Nuriootpa | 39 km (24 mi) | |
| B23 | Main South Road | Old Noarlunga | Aldinga Yankalilla Delamere | Cape Jervis | 75 km (47 mi) | Route continues west over Backstairs Passage to Hog Bay Road on Kangaroo Island |
| B23 | Hog Bay Road Playford Highway | Penneshaw | Pelican Lagoon | Kingscote | 60 km (37 mi) | Route continues east over Backstairs Passage to Main South Road on the South Australian mainland |
| B26 | Greenhill Road | Glenside | Uraidla | Balhannah | 24 km (15 mi) | Allocated in 2019 |
| B27 | Magill Road Old Norton Summit Road Lobethal Road Mount Torrens Road | Kent Town | Norton Summit Basket Range Lobethal | Mount Torrens | 37 km (23 mi) | Allocated in 2019 |
| B28 | Fullarton Road Old Belair Road Upper Sturt Road Waverley Ridge Road Mount Lofty Summit Road | Fullarton | Belair Crafers | Summertown | 25 km (16 mi) | Allocated in 2019 |
| B29 | Unley Road Belair Road Main Road Clarendon Road | Unley | Mitcham Blackwood | Clarendon | 27 km (17 mi) | Allocated in 2020 |
| B31 | Gorge Road Tippet Road North East Road South Para Road Lyndoch Valley Road | Campbelltown | Chain of Ponds Williamstown | Lyndoch | 49 km (30 mi) | Concurrency with along North East Road through Chain of Ponds |
| B33 | Mount Barker Road Strathalbyn Road | Stirling | Aldgate Echunga | Strathalbyn | 37 km (23 mi) | |
| B34 | Warren Road Torrens Valley Road Onkaparinga Valley Road Mount Barker Road Echunga Road Battunga Road Brookman Road Victor Harbor Road Pages Flat Road | Williamstown | Birdwood Willunga Balhannah Echunga | Myponga | 109 km (68 mi) | Concurrencies with: along Victor Harbor Road through Willunga Hill; along Torrens Valley Road through Birdwood |
| B35 | Cricks Mill Road Tungkillo Road Randell Road Reedy Creek Road Mannum Road Swanport Road | Mount Crawford | Mount Pleasant Palmer | Murray Bridge | 63 km (39 mi) | Concurrency with along Torrens Valley Road through Mount Pleasant |
| B36 | Randell Road Mannum Road | Palmer | Mannum | Murray Bridge North | 38 km (24 mi) | |
| B37 | Wellington Road Long Valley Road Alexandrina Road Port Elliot Road Hindmarsh Road Waitpinga Road Range Road | Mount Barker | Strathalbyn Goolwa Port Elliot Victor Harbor | Delamere | 126 km (78 mi) | Concurrency with along Hindmarsh Road through Victor Harbor |
| B45 | Langhorne Creek Road Ferry Road | Strathalbyn | Langhorne Creek | Wellington East | 49 km (30 mi) | |
| B55 | Old Princes Highway Karoonda Highway Bookpurnong Road | Murray Bridge | Karoonda Loxton | Berri | 202 km (126 mi) | |
| B56 | Horrocks Pass Road Willowie Road RM Williams Way Petersburg Road | Winninowie | Wilmington Orroroo | Peterborough | 108 km (67 mi) | Concurrencies with: along RM Williams Way from Orroroo to Black Rock; along Horrocks Highway through Wilmington |
| B57 | Browns Well Highway Mallee Highway Ngarkat Highway Dukes Highway Naracoorte Road | Loxton | Paruna Pinnaroo Ngarkat Bordertown | Cadgee | 292 km (181 mi) | Concurrencies with: along Dukes Highway from Lowan Vale to Bordertown; along Mallee Highway through Pinnaroo |
| B64 | Goyder Highway | Crystal Brook | Spalding Burra Morgan | Monash | 266 km (165 mi) | Concurrencies with: along Barrier Highway through Burra; along RM Williams Way through Spalding; along Horrocks Highway through Gulnare |
| B66 | Riddoch Highway | Mount Gambier | Mount Schank | Port MacDonnell | 28 km (17 mi) | Continues north as along Riddoch Highway to Mount Gambier |
| B77 | Mallala Road Old Port Wakefield Road Gawler Road Two Wells Road Ryde Street Overway Bridge Road Fifteenth Street Twelfth Street | Two Wells | Gawler River | Gawler | 23.5 km (15 mi) | Allocated in 2021 |
| B78 | Wilkins Highway | Jamestown | | Hallett | 38 km (24 mi) | |
| B79 | Wilkins Highway RM Williams Way Beniah Road Petersburg Road | Warnertown | Gladstone Jamestown Peterborough | Ucolta | 104 km (65 mi) | Concurrency with along RM Williams Way from Mannanarie to Jamestown |
| B80 | RM Williams Way | Hawker | Carrieton Orroroo Jamestown Spalding | Barinia | 220 km (137 mi) | Concurrencies with: along RM Williams Way from Orroroo to Black Rock; along Goyder Highway through Spalding; along RM Williams Way from Mannanarie to Jamestown |
| B81 | Thiele Highway | Gawler Belt | Kapunda Eudunda | Morgan | 115 km (71 mi) | |
| B82 | Main North Road Horrocks Highway | Quorn | Wilmington Melrose Gladstone Clare Giles Corner | Gawler Belt | 282 km (175 mi) | Concurrencies with: along Wilmington–Ucolta Road through Wilmington; along Goyder Highway through Gulnare |
| B83 | The Outback Highway Flinders Ranges Way | Lyndhurst | Leigh Creek Hawker Quorn | Stirling North | 292 km (181 mi) | Much of this route still is signed ; shields still visible at Flinders Ranges Way and West Terrace intersection in Quorn |
| B84 | Port Wakefield–Balaklava Road Saddleworth Road Marrabel Road Curio Road | Port Wakefield | Balaklava Auburn Saddleworth Marrabel | Eudunda | 100 km (62 mi) | |
| B85 | Copper Coast Highway | Port Wakefield | Paskeville Kadina | Wallaroo | 58 km (36 mi) | |
| B86 | Yorke Highway | Port Arthur | Ardrossan Minlaton Marion Bay | Stenhouse Bay | 181 km (112 mi) | |
| B88 | St Vincent Highway | Pine Point | Port Vincent Stansbury Edithburgh Yorketown | Warooka | 101 km (63 mi) | |
| B89 | Spencer Highway | Port Pirie | Port Broughton Wallaroo Maitland | Minlaton | 199 km (124 mi) | |
| B90 | Tod Highway | Kyancutta | Lock Cummins | Uley | 176 km (109 mi) | |
| B91 | Birdseye Highway | Elliston | Lock Cleve | Cowell | 198 km (123 mi) | |
| B97 | Pimba Road Olympic Dam Highway | Pimba | Woomera Roxby Downs | Olympic Dam | 89 km (55 mi) | |
| B100 | Flinders Highway Lincoln Highway | Ceduna | Streaky Bay Elliston Port Lincoln Tumby Bay Cowell Whyalla | Lincoln Gap | 715 km (444 mi) | |
| B101 | Southern Ports Highway | Kingston SE | Robe Beachport | Millicent | 119 km (74 mi) | |
| B160 | Glenelg Highway | Glenburnie | | SA/Vic border | 15.3 km (10 mi) | Continues east as along Glenelg Highway into Victoria eventually to Ballarat (a Victorian B route "extended" into SA) |
| B201 | Old Sturt Highway Berri–Renmark Road | Barmera | Berri | Monash | 16.8 km (10 mi) | Former Sturt Highway alignment |

### C routes

Roads allocated a C route are major collector roads, linking local roads and streets to the arterial road network for inter-state travel.
While officially gazetted C routes exist in South Australia, these are currently based on existing Victorian C routes terminating in South Australian locations just inside the SA/Vic state border, and do not exist anywhere else in the state.
| Route | Component roads | From | Via | To | Length | Notes |
| C192 | Glenelg River Road | Mount Gambier | Wye | SA/Vic border | 30 km (19 mi) | Continues east as along Glenelg River Road into Victoria to Portland |
| C198 | Casterton Road | Penola | | SA/Vic border | 17.4 km (11 mi) | Continues east as along Casterton–Penola Road into Victoria to Casterton |
| C212 | Edenhope Road | Wrattonbully | | SA/Vic border | 13.3 km (8 mi) | Continues east as along Edenhope–Penola Road into Victoria to Edenhope |
| C240 | Wimmera Highway | Naracoorte | | SA/Vicborder | 23 km (14 mi) | Continues east as along Wimmera Highway into Victoria to Marong |

### R routes

Roads allocated a R route are for ring roads, provide a path around a city, rather than travelling through it.
South Australia is currently the only state in the country to use R routes. To date, there is only one R route: around Adelaide, the state's capital city.
| Route | Component roads | From | Via | To | Length | Notes |
| R1 City Ring Route | Port Road Park Terrace Fitzroy Terrace Robe Terrace Park Road (s/bound) Mann Road (n/bound) Hackney Road Dequetteville Terrace Fullarton Road Greenhill Road Richmond Road South Road James Congdon Drive | Adelaide | North Adelaide | Adelaide | 16.9 km (11 mi) | Replaced in 2017 on a slightly different alignment to the southwest, listed clockwise from the western corner of Adelaide city centre |

## Former Routes
### National Routes

National Routes were the first type of route numbering to be attempted in Australia on a large scale, signed with a white shield and black writing (similar in shape to the shield that appears on the Australian coat of arms), with South Australia receiving routes in 1955. They highlighted the interstate links connecting major population, industrial and principal regions of New South Wales to the rest of the Australia, in a way that was readily identifiable to interstate travellers. The system was prepared by the Conference of State Road Authorities, held between 1953 and 1954: once each state road authority agreed to the scheme, it was rolled out federally.
Selected routes were later upgraded into National Highways when the National Roads Act was passed in 1974.
South Australia's National Routes were eventually replaced with the alphanumeric system, introduced across the state between 1998 and 1999: each route was converted to an alphanumeric route number, rendering the black-and-white shield redundant. Most National Routes in rural South Australia kept their number during the conversion; two exceptions were National Route 47 (which became B83), and National Route 83 (which became B80, B82 and B83).
| Route | Component roads | From | Via | To | Length | Notes |
| National Route 1 | Eyre Highway Princes Highway (I) Port Wakefield Road Main North Road Fullarton Road Glen Osmond Road Mount Barker Road South Eastern Freeway Princes Highway (II) | SA/WA border | Ceduna Kimba Port Augusta Port Wakefield Adelaide Murray Bridge Tailem Bend Meningie Kingston SE Mount Gambier | SA/Vic border | 1,716 km (1,066 mi) | – progressively reallocated along South Eastern Freeway sections as they opened – replaced by from SA/WA border to Tailem Bend in 1974 |
| National Route 1 | Princes Highway (II) | SA/WA border | Ceduna Kimba Port Augusta Port Wakefield Adelaide Murray Bridge Tailem Bend Meningie Kingston SE Mount Gambier | SA/Vic border | 1,716 km (1,066 mi) | Replaced by: from Mount Gambier to SA/Vic border; from Tailem Bend to Mount Gambier in 1998 |
| Alternate National Route 1 | Flinders Highway Lincoln Highway | Ceduna | Streaky Bay Elliston Port Lincoln Tumby Bay Cowell Whyalla | Lincoln Gap | 715 km (444 mi) | Allocated after road sealing and upgrades of Flinders Highway completed in 1978, replaced by in 1999 |
| Alternate National Route 1 | Southern Ports Highway | Kingston SE | Robe Beachport | Millicent | 119 km (74 mi) | – former Princes Highway alignment (bypassed in 1933) – allocated in 1978, replaced by in 1999 |
| Alternate National Route 1 | Adelaide Road Old Princes Highway | White Hill | Murray Bridge | Long Flat | 13.2 km (8 mi) | Allocated when Swanport Bridge over the Murray River opened in 1979, replaced by from White Hill to Murray Bridge East in 1998 |
| National Route 8 | Dukes Highway | Tailem Bend | Coonalpyn Tintinara Keith Bordertown | SA/Vic border | 192 km (119 mi) | Replaced by in 1974 |
| National Route 12 | Mallee Highway | Tailem Bend | Lameroo Pinnaroo | SA/Vic border | 145 km (90 mi) | Replaced by in 1998 |
| National Route 20 | Main North Road Gawler Bypass Sturt Highway | Gepps Cross | Elizabeth Gawler Nurioopta Waikerie Barmera Renmark | SA/Vic border | 267 km (166 mi) | Replaced by in 1992 |
| Alternative National Route 20 | Old Sturt Highway | Barmera | Berri | Monash | 16.8 km (10 mi) | Former Sturt Highway alignment, replaced by in 1999 |
| National Route 32 | Main North Road Barrier Highway | Gawler | Giles Corner Saddleworth Burra Ucolta | SA/NSW border | 417 km (259 mi) | Replaced by in 1998 |
| National Route 47 | Flinders Ranges Way | Hawker | Quorn | Stirling North | 98 km (61 mi) | Replaced by in 1998 |
| National Route 56 | Wilmington–Ucolta Road | Winninowie | Orroroo Peterborough | Ucolta | 123 km (76 mi) | Replaced by in 1998 |
| National Route 64 | Goyder Highway | Crystal Brook | Spalding Burra Morgan | Monash | 266 km (165 mi) | Replaced by in 1998 |
| National Route 83 | The Outback Highway (Barndioota Road) | Lyndhurst | Leigh Creek Hawker Clare | Giles Corner | 292 km (181 mi) | Replaced by in 1998 |
| National Route 83 | RM Williams Way | Lyndhurst | Leigh Creek Hawker Clare | Giles Corner | 292 km (181 mi) | Replaced by in 1998 |
| National Route 83 | Main North Road | Lyndhurst | Leigh Creek Hawker Clare | Giles Corner | 292 km (181 mi) | Replaced by in 1998 |
| National Route 87 | Stuart Highway | SA/NT border | Marla Coober Pedy Pimba | Port Augusta West | 928 km (577 mi) | Replaced by in 1974 |
| Decommissioned or unsigned allocation |||||||

### National Highways

With the passing of the National Roads Act in 1974, selected National Routes were further upgraded to the status of a National Highway: interstate roads linking Australia's capital cities and major regional centres that received federal funding, and were of higher importance than other National Routes. These new routes were symbolised by green shields with gold writing, and the word "National" along the top of the shield. Most of South Australia's National Highways were declared in 1974 and their shields converted in the following years, with National Highway 20 later declared in 1992.
Like National Routes, South Australia's National Highways were also replaced with the alphanumeric system, introduced across the state in 1998: each route was converted to an alphanumeric route number, all keeping their number during the conversion, but also initially keeping the National green-and-gold shield design; this was eventually eliminated in 2017.
| Route | Component roads | From | Via | To | Length | Notes |
| National Highway 1 | Eyre Highway Princes Highway (I) Port Wakefield Road Main North Road Fullarton Road Glen Osmond Road Mount Barker Road | SA/WA border | Ceduna Kimba Port Augusta Port Wakefield Adelaide Murray Bridge | Tailem Bend | 1,716 km (1,066 mi) | – replaced by in 1998, being progressively replaced by from 2017 – Princes Highway (I) renamed Augusta Highway in 2011 |
| National Highway 1 | South Eastern Freeway | SA/WA border | Ceduna Kimba Port Augusta Port Wakefield Adelaide Murray Bridge | Tailem Bend | 1,716 km (1,066 mi) | – progressively reallocated along South Eastern Freeway sections as they opened eventually to Murray Bridge in 1979 – replaced by in 1998, being progressively replaced by from 2017 |
| National Highway 1 | Princes Highway (II) | SA/WA border | Ceduna Kimba Port Augusta Port Wakefield Adelaide Murray Bridge | Tailem Bend | 1,716 km (1,066 mi) | Replaced by in 1998, being progressively replaced by from 2017 |
| National Highway 8 | Dukes Highway | Tailem Bend | Coonalpyn Tintinara Keith Bordertown | SA/Vic border | 192 km (119 mi) | – western end re-aligned from Tailem Bend to Coomandook through Cooke Plains in 1980 – re-aligned through Bordertown when Bordertown bypass opened in 1987 – replaced by in 1998, being progressively replaced by from 2017 |
| National Highway 20 | Main North Road Gawler Bypass Sturt Highway | Gepps Cross | Elizabeth Gawler Nurioopta Waikerie Barmera Renmark | SA/Vic border | 267 km (166 mi) | Replaced by in 1998, being progressively replaced by from 2017 |
| National Highway 87 | Stuart Highway | SA/NT border | Marla Coober Pedy Pimba | Port Augusta West | 928 km (577 mi) | Replaced by in 1998, being progressively replaced by from 2017 |
| Decommissioned or unsigned allocation |||||||

### State Routes (from Victoria)

South Australia never adopted State Routes, but allowed two Victorian rural State Routes to cross the border and terminate in South Australian locations within 20 km of it when they were rolled out there in 1985; these were replaced by their Victorian equivalent alphanumeric allocations in 1998.
| Route | Component roads | From | To | Length | Notes |
| State Route 112 | Glenelg Highway | Glenburnie | SA/Vic border | 15.3 km (10 mi) | Continued east as along Glenelg Highway into Victoria eventually to Ballarat; replaced by in 1998 |
| State Route 130 | Wimmera Highway | Naracoorte | SA/Vic border | 23 km (14 mi) | Continued east as along Wimmera Highway into Victoria eventually to St Arnaud; replaced by in 1998 |
| Decommissioned or unsigned route |||||||