It passes through Queensland's Darling Downs region. Typical of the scenery are grazing cattle, orchards and grain farmland. It was elevated to National Highway status in February 1993, and replaced the Cunningham Highway as the main route between Goondiwindi and Brisbane. Interstate traffic is rerouted through Toowoomba and the Warrego Highway as it presents a less steep gradient than via Warwick and Cunninghams Gap, shortening travel time especially for trucks. It was initially designated State Route 85 until February 1993 when National Highway 85 was proclaimed, splitting State Route 85 into two. In 2005 it was given the National Highway A39 designation.