Princes Highway is a major road in Australia, extending from Sydney via Melbourne to Adelaide through the states of New South Wales, Victoria and South Australia. It has a length of 1,941 kilometres (1,206 mi) 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.

Australia's Highway 1 is a network of highways that circumnavigate the country, joining all mainland capital cities except the national capital of Canberra. At a total length of approximately 14,500 km (9,000 mi) it is the longest national highway in the world, surpassing the Trans-Siberian Highway and the Trans-Canada Highway. Over a million people traverse some part of the highway network every day. It is the longest continuing highway in the world as the Pan-American Highway is separated by the Darién Gap and AH1 is separated by the Sea of Japan.