The Nanshi River (Chinese: 南勢溪; DT: Lamsiw kev) is a river in Taiwan. It flows through Wulai District, New Taipei City, some little southern part of Xindian District, New Taipei, and Yilan County for 45km. And, it's one of tributaries of Xindian River. At Guishan, Xidian, it combines with Peishih River to form Xindian River. Forward, its down reach has many scenic spots.