The highway starts in a north-easterly direction from the Gore suburb of McNab to the locality of Willowbank, where the highway turns right at an at-grade T intersection.

The road crosses the Southland/Otago boundary via a series of rolling hills into Waikoikoi.

The highway veers back to the northeast and crosses the Pomahaka River to enter Tapanui.

The highway passes through Crookston and runs parallel with the Blue Mountains until it reaches Edievale where the road curves to the east.

The highway then begins to descend towards the Clutha Valley before terminating at Raes Junction.