The Coldwater River is located in south central British Columbia, Canada. It is the largest tributary of the Nicola River, which it joins at the city of Merritt. The river drains a watershed of 917 square kilometres (354 sq mi). The English name derives from the Secwepemc (Shuswap) name for the river, Ntstlatko, meaning "cold water", although the river lies south of Secwepemc traditional territory and entirely within the traditional territory of the Nlaka'pamux First Nation.

Merritt is a city in the Nicola Valley of the south-central Interior of British Columbia, Canada. It is 270 km (170 mi) northeast of Vancouver. Situated at the confluence of the Nicola and Coldwater rivers, it is the first major community encountered after travelling along Phase One of the Coquihalla Highway and acts as the gateway to all other major highways to the B.C. Interior. The city developed in 1893 when part of the ranches owned by William Voght, Jesus Garcia, and John Charters were surveyed for a town site.