The Luan River ( zh, c=滦河, p=Luánhé, formerly known as ''Lei Shui'', or ''Ru Shui'') is a river in China.

River

The river flows northwards from its source in the province of

Hebei Hebei is a Provinces of China, province in North China. It is China's List of Chinese administrative divisions by population, sixth-most populous province, with a population of over 75 million people. Shijiazhuang is the capital city. It bor ...

into the province of

Inner Mongolia Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an Autonomous regions of China, autonomous region of China. Its border includes two-thirds of the length of China's China–Mongolia border, border with the country of Mongolia. ...

, and then flows southeast back into

to its mouth on the

Bohai Sea The Bohai Sea ( zh, c=渤海, p=Bó Hǎi, l=Bo Sea) is a gulf/inland 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 via the Bohai Strait. It ...

. The

headstream The headwater of a river or stream is the geographical point of its beginning, specifically where surface runoff water begins to accumulate into a flowing channel of water. A river or stream into which one or many tributary rivers or streams flo ...

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

Shangdu Shangdu (; lit. "Upper Capital"; ), known in the West as Xanadu, was the summer capital of the Yuan dynasty under Kublai Khan. Located in what is now Zhenglan Banner, Inner Mongolia, it was designed by Chinese architect Liu Bingzhong and served as ...

. 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, wa ...

, 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 northeast of Beijing. It is best known as the site of the Mountain Resort, a vast imperial garden and palace formerly used by the Qing e ...

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 impact ...

suggests there is an

impact crater An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...

in the area. It is estimated to be between 70 and 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