The Luan River
, 滦河, formerly known as Lei Shui
, or Ru Shui
) is a river
. It flows northwards from its source in the province of Hebei
into the province of Inner Mongolia
, and then flows southeast back into Hebei
to its mouth on the Bohai Sea
. Its length is about 600 km. One subsidiary of the Luan River is the Yixun He
, which runs through Hebei.
The largest city on the course of the river is Chengde.