Great Northern Highway links Western Australia's capital city Perth with its northernmost port, Wyndham. With a length of almost , it is the longest highway in Australia, with the majority included as part of the Perth Darwin National Highway. The highway is constructed as a sealed, predominantly two-lane single carriageway, but with some single-lane bridges in the Kimberley. Great Northern Highway travels through remote areas of the state, and is the only sealed road link between the Northern Territory and northern Western Australia. Economically, it provides vital access through the Wheatbelt and Mid West to the resource-rich regions of the Pilbara and Kimberley. In these areas, the key industries of mining, agriculture and pastoral stations, and tourism are all dependent on the highway.