Mount Barker Road was once the main road from Adelaide through the Adelaide Hills to Mount Barker on the eastern slopes of the Mount Lofty Ranges. The main route has now been replaced, or subsumed into, the South Eastern Freeway, but two sections of it remain, and are still classified as state roads.

South Eastern Freeway is a 73 km (45 mi) freeway in South Australia (SA). It is a part of the National Highway network linking the state capital cities of Adelaide, SA, and Melbourne, Victoria, and is signed as route M1. It carries traffic over the Adelaide Hills between Adelaide and the River Murray, near Murray Bridge, where it is connected via the Swanport Bridge to the Dukes Highway, which is the main road route to Victoria.