Kok River


The Kok River is a tributary river of the Mekong that flows in Chiang Rai and Chiang Mai provinces in northern Thailand.

Tributaries

The main tributaries of the Kok River are the Fang and the Lao River, the latter having its source in the Phi Pan Nam Range.

Dams

There is a small dam with 11 gates which provides irrigation for rice fields east of Chiang Rai. The dam is east of the Hwy 1 bridge. It turns the river into a lake, several miles long, for eight months of the year. Additionally, there is a dam planned on the Burmese side of where the river flows into Thailand, about upstream from the border.

''Top Gear''

In October 2013 the cast and crew of the British television show Top Gear constructed a bridge over the Kok as part of their Burma Special. The bridge was originally planned to be built over the River Kwai, but the River Fang which flows into the Kok was chosen "accidentally". The show aired in two parts on 9 March 2014 and 16 March 2014.
Following production of the episode, the bridge was taken down, despite the producers and crew wanting it to stay in use for the locals.

2025 contamination

In March 2025, it was reported that the section of the Kok river in Chiang Mai had turned unusually cloudy and people were developing rashes after swimming. Testing of water samples by Thai authorities found the turbidity to be ten times above standard and also detected unsafe levels of lead and arsenic. Gold mining upstream in Myanmar was suspected to be the cause., tests continue to show contamination.