Wairau Valley is the valley of the Wairau River in Marlborough, New Zealand and also the name of the main settlement in the upper valley. State Highway 63 runs through the valley. The valley opens onto the Wairau Plain, where Renwick and Blenheim are sited. The Alpine–Wairau Fault runs along the length of the valley. Wairauite is an iron-cobalt alloy which is named after the valley.