It flows south-east and east along the Alaska Highway, receiving the waters of Dease River, Kloye Creek, Trepanier Creek and Black Angus Creek. It continues east through the Dease Forest, where it receives the waters of the Hyland River south of Hyland River Provincial Park, then receives the Malcolm Creek, Tatisno Creek and Nustlo Creek. It flows along the Yukon border, where the Alaska Highway once again follows the Liard and receives the Cosh Creek, Contact Creek, Scoby Creek and Sandin Brook, then turns south around Mount Sandin, receiving water from Tsia Creek, Tsinitla Creek, Tatzille Creek and Leguil Creek. It turns eastwards along the northern margin of the Liard Plateau, where it receives the Kechika River near Skooks Landing, Niloil Creek from Niloil Lake and Coal River by Coal River. It continues east and south-east, south of Mount Reid, still followed by the Alaska Highway, receiving the waters of Geddes Creek, Grant Creek, Smith River, Lapie Creek, Teeter Creek, Mould Creek and Hoole Creek.
It enters the Liard River Hot Springs Provincial Park, where the Trout River empties into the Liard. Alaska Highway runs south along the Trout River, while the Liard flows east through the Liard River Corridor Provincial Park and Protected Area, south of the Sentinel Range of the Muskwa Ranges, receiving the waters of Deer River and Canyon Creek in the Grand Canyon of the Liard. It continues south-east between the Barricade Range and Mount Rothenberg of the Sentinel Range, where the Moule Creek and Sulphur Creek flow in the Liard. It flows east, out of the Northern Rockies and through the foothills, where it receives waters from the Brimstone Creek, Crusty Creek, Grayling River, Graybank Creek and Toad River. It turns north-west, receiving the waters from Garbutt Creek, Lepine Creek, Chimney Creek, Ruthie Creek, Scatter River and Beaver River. It then turns south-east, receives the waters from Catkin Creek, Dunedin River and Fort Nelson River. From here it turns north, receiving the waters of Zus Creek, Sandy Creek and La Biche River and crosses into the Northwest Territories, immediately east of the Yukon border.