Flinders Highway connects the South Australian towns of Ceduna and Port Lincoln, a distance of 410 kilometres. The highway was formerly designated as National Route Alternate 1 and currently signed as B100. Route B100, formerly National Route Alternate 1 (from 1978 to 1999), consisting of the Flinders Highway and Lincoln Highway, presents an alternative but somewhat longer coastal route between Port Augusta and Ceduna, compared to the more direct Eyre Highway.
The Flinders Highway runs parallel to the western coast of the Eyre Peninsula through undulating farmland. It is named after the explorer Matthew Flinders who sighted these coasts in early 1802 from HMS Investigator. Only small settlements lie along its track. Of these, Coffin Bay is a centre for oyster farming, Elliston is renowned for swimming beaches and fishing and Ceduna is the main town on the far west coast of South Australia supporting government offices and businesses.