Steung Saen River

The Steung Saen River, also known as the Steung Sen River, is a river in Cambodia. It is a major tributary of the Tonlé Sap, a lake in northwest Cambodia that is part of the Mekong River system, the largest freshwater lake in Southeast Asia, and one of the world's most diverse and productive ecosystems, designated as a Biosphere Reserve by UNESCO in 1997 due to its high biodiversity. With a catchment area of 16,344 km2, the Stung Sen River Basin is the largest of the 11 major tributaries surrounding Tonlé Sap (1,634,400 ha). Each year, the basin receives approximately 1,500 mm (59 in) of rain.

The river flows through Preah Vihear and Kampong Thom provinces. The river basin's northern extent corresponds to Thailand's border, as in 1904, Siam and the French colonial authorities ruling Cambodia formed a joint commission to demarcate their mutual border, which largely follows the watershed line of the Dângrêk mountain range.

In Khmer, Steung Saen means "river of soldiers." Steung means "river" in Khmer, whereas Saen is derived from the Sanskrit word Sena, which means "soldier."

Length: 520 km (320 mi)