The Loei River is the one of tributaries of the Mekong River. It originates at the western shore of the Phu Luang plateau

Phu Luang Wildlife Sanctuary

Phu Luang Wildlife Sanctuary is a wildlife sanctuary in northern Thailand, located in the south of Loei Province.It covers an area of 897 km², covering area of the tambon Pla Ba and Tha Sala of Phu Ruea district, Phon Sung, Wang Yao and I Pum of Dan Sai, Nong Ngio and Saikhao of Wang Saphung, and...

, at first flowing southwards. Changing to an eastward direction it becomes the boundary between Loei and Phetchabun Province

Phetchabun Province

Phetchabun is one of the northern provinces of Thailand. Neighboring provinces are Loei, Khon Kaen, Chaiyaphum, Lopburi, Nakhon Sawan, Phichit and Phitsanulok.- Geography :...

, encircles the Phu Ho mountain and then flows northwards across the town Loei

Loei

Loei is a town in the north-east of Thailand. In 2005, it had a population of 22,677. Loei covers the whole tambon Kut Pong of Mueang Loei district.Loei is the capital of the Loei Province.- References :...

 until it and mouths to the Mekong River in Na Sao Subdistrict, Chiang Khan District

Amphoe Chiang Khan

Chiang Khan is a district in the northern part of Loei Province, northeastern Thailand.-Geography:Neighboring districts are Pak Chom, Mueang Loei and Tha Li of Loei Province...

.