In South Australia, Highway 1 is a 1,717-kilometre (1,067 mi) long route that follows the coastline of the state, from the Victorian border near Mount Gambier to the Western Australian border near Eucla. Highway 1 continues around the rest of Australia, joining all mainland state capitals, and connecting major centres in Tasmania. All roads within the Highway 1 system are allocated a road route numbered 1, M1, A1, or B1, depending on the state route numbering system, and parts are concurrent with National Highway routes. In South Australia, most of the highway is designated as route A1, with multi-lane, dual-carriage-way sections generally designated route M1. South-east of Tailem Bend, it is designated route B1.