Simpang-kiri River (Indonesian: Sungai Simpangkiri, means: Left Junction River) is a river in Riau province, central-eastern Sumatra, Indonesia, about 800 km northwest of the capital Jakarta.

[2][3] 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 26 °C, and the coldest is January, at 23 °C.

[5] The average annual rainfall is 2667 mm.

The wettest month is November, with an average of 402 mm rainfall, and the driest is June, with 104 mm rainfall.