South Western Highway is a highway in the South West region of Western Australia connecting Perth's southeast with Walpole. It is a part of the Highway 1 network for most of its length. It is about 406 kilometres (252 mi) long.

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.