Sepik

For other uses, see Sepik (disambiguation).

Sepik
Sediment plumes at the mouth of the Sepik (right) and Ramu (left) rivers
Sepik River watershed (Interactive map)
Location
Country	Papua New Guinea, Indonesia
Region	Sandaun, Papua, East Sepik
Physical characteristics
Source
• location	Victor Emanuel Range
• coordinates	5°13′S 141°49′E
• elevation	2,170 m (7,120 ft)
Mouth
• location	Bismarck Sea, Papua New Guinea
• coordinates	3°50′30″S 144°32′30″E
• elevation	0 m (0 ft)
Length	1,126 km (700 mi)
Basin size	80,321 km2 (31,012 sq mi)
Width
• average	400–500 m (1,300–1,600 ft)
Depth
• minimum	2 m (6 ft 7 in)
• average	8–14 m (26–46 ft)
• maximum	35–55 m (115–180 ft) (Angoram)
Discharge
• location	Angoram
• average	5,000 m3/s (180,000 cu ft/s)
Discharge
• location	Ambunti
• average	3,615 m3/s (127,700 cu ft/s)
Basin features
Progression	Bismarck Sea
River system	Sepik River
Tributaries
• left	Iram, Brucken, Oklip, Hauser, Horden, North, Yellow, Sanchi, Yimi, Nagam
• right	Hak, August, May, Seniap, Frieda, Wario, Wagamush, April, Karawari, Yuat, Keram, Bien

The Sepik (/ˈsiːpɪk/) is the longest river on the island of New Guinea, and the third largest in Oceania by discharge volume after the Fly and Mamberamo. The majority of the river flows through the Papua New Guinea (PNG) provinces of Sandaun (formerly West Sepik) and East Sepik, with a small section flowing through the Indonesian province of Papua.

The Sepik has a large catchment area, and landforms that include swamplands and mountains. Biologically, the river system is often said to be possibly the largest uncontaminated freshwater wetland system in the Asia-Pacific region. Numerous fish and plant species have been introduced into the Sepik since the mid-20th century.