The Yellow River is divided into three distinct parts: the mountainous upper course, the middle course across a plateau, and the lower course across a low plain.

Past the gorges, near the city of Lanzhou in southeastern Gansu province, it leaves the Plateau of Tibet. That transition marks the end of the upper Yellow River, which is some 725 miles (1,165 km) from its source. The upper course drains a basin covering about 48,000 square miles (124,000 square km), consisting chiefly of inaccessible, highly mountainous, sparsely populated terrain with a cold climate.

The Yellow River originates at an elevation above 15,000 feet (4,600 metres) in the Bayan Har Mountains , in the eastern Plateau of Tibet. In its upper reaches the river crosses two large bodies of water, Lakes Ngoring and Gyaring. Those shallow lakes, each covering an area of about 400 square miles (1,000 square km), are rich in fish and freeze over in winter. The Yellow River in that region flows generally from west to east. The broad highlands of the upper course rise 1,000 to 1,700 feet (300 to 500 metres) above the river and its tributaries. The highlands consist of crystalline rocks that are sometimes visible as eroded outcroppings on the surface. The river enters a region of deep gorges, winding its way first southeast, then northwest around the A’nyêmaqên (Amne Machin) Mountains, where its fall exceeds 10 feet per mile (2 metres per km), and then east again between the Xiqing and Laji mountains.

The middle course

The middle course of the Yellow River, extending more than 1,800 miles (2,900 km), consists of a great loop and drains an area of about 23,000 square miles (60,000 square km). The river at first flows northeast for about 550 miles (880 km) through the sandy soils of the northern Hui Autonomous Region of Ningxia and of the western Ordos Plateau. It has many rapids there, and in a number of places it narrows. The river then turns eastward and flows for another 500 miles (800 km) through alluvial plains in the Inner Mongolia Autonomous Region, in places branching into numerous distributary channels. In that stretch its fall is less than half a foot per mile (9 cm per km), and many of the channels have been developed over the millennia for irrigated agriculture.

Lanzhou Portion of the Huang He (Yellow River) at Lanzhou, Gansu province, northwestern China.

aerial footage of the Huang He Aerial footage of the Huang He (Yellow River) at Linfen, Shanxi province, and of the Hukou Falls, which form the border between Shanxi (at Linfen) and Shaanxi (at Yan'an) provinces, China. © CCTV America (A Britannica Publishing Partner) See all videos for this article

The Yellow River then turns sharply to the south and flows for about 445 miles (715 km), forming the border between Shaanxi and Shanxi provinces. The river’s width usually does not exceed 150 to 200 feet (45 to 60 metres) in that section, as it cuts through narrow gorges with steep slopes several hundred feet (above 100 metres) in height. The river then gradually widens, notably after receiving the waters of its two longest tributaries—first the Fen River of Shanxi province and then the Wei River of Shaanxi. At the confluence with the Wei, the Yellow River turns sharply to the east for another 300 miles (480 km) as it flows through inaccessible gorges between the Zhongtiao and eastern Qin (Tsinling) mountains. The average fall in that stretch is slightly more than 1 foot per mile (20 cm per km) and becomes increasingly rapid in the last 100 miles (160 km) before the river reaches the North China Plain at the city of Zhengzhou in Henan province.

Most of the middle course is cut through the Loess Plateau, which extends eastward from the Plateau of Tibet to the North China Plain at elevations ranging between 3,000 and 7,000 feet (900 and 2,100 metres). The plateau contains terraced slopes as well as alluvial plains and a scattering of peaks sometimes rising more than 1,500 feet (450 metres) above the plateau. The river has cut at least six terraces across the plateau, which rise to more than 1,600 feet (500 metres) above the present river level. The terraces, formed over the past 2.5 million years, provide an important record of landscape evolution and ancient environmental change in the region. The underlying rock systems are covered with thick layers of loose soils, consisting mainly of wind-deposited sand and loess. The loess strata reach thicknesses of 160 to 200 feet (50 to 60 metres) and in some places as much as 500 feet (150 metres). Through those loose deposits the river has cut deep valleys, carrying away with it huge quantities of surface material, making that region one of the most highly eroded landscapes in the world. The easily eroded loess soil accounts for the instability of the riverbed both in the middle basin, where the erosion is considerable, and on the plain, where deposition builds up the channel bed.