Rokan River is a river in Riau province, central-eastern Sumatra, Indonesia, about 1,100 km northwest of the capital Jakarta.

[2][3] The river originates in the Barisan Mountains in the west, and drains northeast-ward along Rokan Hulu Regency and Rokan Hilir Regency with estuarine located near the port town of Bagansiapiapi draining the water to Malacca Strait.

The river flows in the central area of Sumatra with predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification).

The warmest month is March, when the average temperature is around 24 °C, and the coldest is January, at 22 °C.

The wettest month is November, with an average of 336 mm rainfall, and the driest is July, with 113 mm rainfall.