[1] The upper course of the river was the location of the Ulu Aik Kingdom (est.

The Krio River rapids are reached by starting from Pontianak in the direction of Ketapang by speedboat for six hours, then a four-hour trip in a smaller boat.

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

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

The wettest month is December, with an average of 495 mm rainfall, and the driest is August, with 160 mm rainfall.