| Mendawai River | |
| Name Other: | Soengai Katingin, Soengai Mendawei, Soengai Ketingan, Mendawi, Soengai Katingan |
| Pushpin Map: | Indonesia |
| Subdivision Type1: | Country |
| Subdivision Name1: | Indonesia |
| Subdivision Type2: | Province |
| Subdivision Name2: | Central Kalimantan |
| Discharge1 Location: | Katingan Kuala (Katingan Regency), Java Sea (near mouth) |
| Discharge1 Avg: | 1414m3/s[1] |
| Source1: | Schwaner Mountains |
| Mouth Location: | Pagatan |
| Mouth Coordinates: | -3.0854°N 131.6542°W |
| River System: | Katingan basin (DAS320369)[2] |
| Basin Size: | 19500km2 |
| Discharge2 Location: | Kasongan |
| Discharge2 Avg: | 1279m3/s[3] |
| Qid: | Q24878211 |
Mendawai River or Katingan River is a river of Borneo, it is located in Central Kalimantan, Indonesia. With a total length of .[4] [5] The longhouses of the Pendahara are located along the river in its upper course. The river has its source in the Schwaner Mountain Range.[6]
The river flows in the southeast area of Borneo with predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification).[7] The annual average temperature in the area is 22 °C. The warmest month is September, when the average temperature is around 24 °C, and the coldest is December, at 20 °C.[8] The average annual rainfall is 2991 mm. The wettest month is December, with an average of 476 mm rainfall, and the driest is September, with 75 mm rainfall.[9]