The Princes Highway is a major road in Australia, extending from Sydney to Port Augusta via the coast through the states of New South Wales, Victoria and South Australia. It has a length of 1,941 kilometres (1,206 mi) (along Highway 1) or 1,898 kilometres (1,179 mi) via the former alignments of the highway, although these routes are slower and connections to the bypassed sections of the original route are poor in many cases.
The highway follows the coastline for most of its length, and thus takes quite an indirect and lengthy route. For example, it is 1,040 kilometres (650 mi) from Sydney to Melbourne on Highway 1 as opposed to 870 kilometres (540 mi) on the more direct Hume Highway (National Highway 31), and 915 kilometres (569 mi) from Melbourne to Adelaide compared to 730 kilometres (450 mi) on the Western and Dukes Highways (National Highway 8). Because of the rural nature and lower traffic volumes over much of its length, the Princes Highway is a more scenic and leisurely route than the main highways between these major cities.