The Nanxi River, also known as the Nậm Thi River in Vietnamese or Namiti, is a tributary of the Red River located in China's Yunnan province. It is a border river of Lào Cai, Vietnam, and Hekou, China
The Yunnan–Vietnam Railway crosses the Nanxi River from Hekou, China (left) to Lao Cai, Vietnam (right) on a bridge a short distance upstream from the river's mouth