Starting at a sharply angled junction on the A629 at Denholme Clough the road headed south across the moors to Queensbury where it crossed the A647. The road descended through Stone Chair and Hipperholme to reach the valley of the River Calder and Brighouse. It ended to the west of the town centre on the original line of the A643 (now A6025).
The entire road was renumbered as an extension of the A644 in 1935. The northernmost section of the road is now one-way southbound owing to the sharp angle of the junction and the narrow road; northbound traffic has to bear left to meet the A629 half a mile further south.