The Luan River (, formerly known as ''Lei Shui'', or ''Ru Shui'') is a

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

River

The river flows northwards from its source in the province of

Hebei Hebei or , (; alternately Hopeh) is a northern province of China. Hebei is China's sixth most populous province, with over 75 million people. Shijiazhuang is the capital city. The province is 96% Han Chinese, 3% Manchu, 0.8% Hui, an ...

into the province of

Inner Mongolia Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an autonomous region of the People's Republic of China. Its border includes most of the length of China's border with the country of Mongolia. Inner Mongolia also accounts for a ...

, and then flows southeast back into

to its mouth on the

Bohai Sea The Bohai Sea () is a marginal sea approximately in area on the east coast of Mainland China. It is the northwestern and innermost extension of the Yellow Sea, to which it connects to the east via the Bohai Strait. It has a mean depth of a ...

. The

headstream The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The ...

is known as Shandian River. This part of the river flows near the ancient Mongol capital city of

Shangdu Shangdu (, ), also known as Xanadu (; Mongolian: ''Šandu''), was the summer capital of the Yuan dynasty of China before Kublai decided to move his throne to the former Jin dynasty capital of Zhōngdū () which was renamed Khanbaliq ( presen ...

. Another important settlement in this section is Duolun. From here, the river's course turns to the southeast. Its length is about 600 km. One subsidiary is the

Yixun He The Yixun River () is a subsidiary of Luan He, a river located in Hebei, a province of the People's Republic of China. History Until the name was changed to Luan He during the Ming Dynasty The Ming dynasty (), officially the Great Ming, w ...

, which runs through Hebei. During its course, the Luan also passes by the Great Wall. After Chengde, the river is navigable. The largest city along the river's course is

Chengde Chengde, formerly known as Jehol and Rehe, is a prefecture-level city in Hebei province, situated about 225 km northeast of Beijing. It is best known as the site of the Mountain Resort, a vast imperial garden and palace formerly used by t ...

Impact crater

Geological evidence such as the presence of

suevite Suevite is a rock consisting partly of melted material, typically forming a breccia containing glass and crystal or lithic fragments, formed during an impact event. It forms part of a group of rock types and structures that are known as imp ...

suggests there is an

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

in the area. It is estimated to be between 70–170 km in diameter with an age of 129 ± 3 Ma. The circular course of Luan River as it goes from Inner Mongolia back to Hebei is said to define part of the crater's outline.

References

Rivers of Hebei Rivers of Inner Mongolia {{China-river-stub