Riddoch Highway

Riddoch Highway South Australia
The Riddoch Highway near Padthaway
North end South end
Coordinates	36°05′09″S 140°20′33″E / 36.085721°S 140.342395°E / -36.085721; 140.342395 (North end) 38°03′12″S 140°42′09″E / 38.053398°S 140.702383°E / -38.053398; 140.702383 (South end)
General information
Type	Highway
Length	239 km (149 mi)[1]
Route number(s)	A66 (1998–present) (Keith–Mount Gambier) B66 (1998–present) (Mount Gambier–Port MacDonnell)
Major junctions
North end	Dukes Highway Keith, South Australia
	Bordertown–Naracoorte Road Wimmera Highway Edenhope-Penola Road Princes Highway
South end	Sea Parade Port MacDonnell, South Australia
Location(s)
Region	Limestone Coast[2]
Major settlements	Padthaway, Naracoorte, Coonawarra, Penola, Tarpeena, Mount Gambier
Highway system
Highways in Australia National Highway • Freeways in Australia Highways in South Australia
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Riddoch Highway is a rural highway in south-eastern South Australia, designated as route A66 between Keith and Mount Gambier, with the remainder between Mount Gambier and Port MacDonnell designated as route B66. It is named after John Riddoch, the first white settler landholder and vigneron in Coonawarra.