List of largest unfragmented rivers

Rank River Basin countries Length of longest channel Drainage area Average discharge (m³/s) Average annual discharge Mouth Notes 1 Fly River Papua New Guinea
Indonesia 1,050 kilometres (650 mi) 76,000 square kilometres (29,000 sq mi) 6,000 cubic metres per second (210,000 cu ft/s) 189 cubic kilometres (45 cu mi) Gulf of Papua Largest river with no dam in its catchment 2 Mamberamo River Indonesia 4,580 cubic metres per second (162,000 cu ft/s) 144.5 cubic kilometres (34.7 cu mi) Pacific Ocean Largest river in all of Indonesia 3 Pechora River Russia 1,809 kilometres (1,124 mi) 322,000 square kilometres (124,000 sq mi) 4,100 cubic metres per second (140,000 cu ft/s) 129 cubic kilometres (31 cu mi) Arctic Ocean Once the subject of a possible transfer of water into the Volga. 4 Sepik River Papua New Guinea
Indonesia 1,126 kilometres (700 mi) 80,321 square kilometres (31,012 sq mi) 3,804 cubic metres per second (134,300 cu ft/s) 120 cubic kilometres (29 cu mi) Pacific Ocean Often regarded as largest completely pristine river system in the world 5 Kaladan River Burma
India 350 kilometres (220 mi) 30,500 square kilometres (11,800 sq mi)^[2] 3,476 cubic metres per second (122,800 cu ft/s) 110 cubic kilometres (26 cu mi) Bay of Bengal Discharge estimated in absence of streamgauges.
Dredging project by Indian and Myanmar governments. 6 Kikori River Papua New Guinea 320 kilometres (200 mi) 23,300 square kilometres (9,000 sq mi) 3,274 cubic metres per second (115,600 cu ft/s) 103 cubic kilometres (25 cu mi) Gulf of Papua 7 Khatanga River Russia (Krasnoyarsk Krai) 1,150 kilometres (710 mi) 364,000 square kilometres (141,000 sq mi) 3,200 cubic metres per second (110,000 cu ft/s) 101 cubic kilometres (24 cu mi) Arctic Ocean Most northerly large river system in the world, with northernmost tree line in basin. 8 Purari River Papua New Guinea 470 kilometres (290 mi) 33,670 square kilometres (13,000 sq mi) 2,571 cubic metres per second (90,800 cu ft/s) 81 cubic kilometres (19 cu mi) Gulf of Papua Hydroelectric dam proposed by Queensland government, so may need to be removed from list^[3] 9 Atrato River Colombia 750 kilometres (470 mi) 38,600 square kilometres (14,900 sq mi) 2,274 cubic metres per second (80,300 cu ft/s) 71 cubic kilometres (17 cu mi) Pacific Ocean Some estimates place discharge much higher – possibly placing the Atrato second only to the Fly^[4] 10 Pyasina River Russia (Krasnoyarsk Krai) 818 kilometres (508 mi) 182,000 square kilometres (70,000 sq mi) 2,260 cubic metres per second (80,000 cu ft/s) 71 cubic kilometres (17 cu mi) Arctic Ocean Norilsk, most northerly city over 100,000, located on main stem of river. 11 Essequibo River Guyana
Venezuela 1,000 kilometres (620 mi)^[5] 69,000 square kilometres (27,000 sq mi) 2,213 cubic metres per second (78,200 cu ft/s) 70 cubic kilometres (17 cu mi) Caribbean Sea Largest completely unfragmented river flowing into Atlantic. 12 Anadyr River Russia 1,150 kilometres (710 mi) 191,000 square kilometres (74,000 sq mi) 2,020 cubic metres per second (71,000 cu ft/s) 64 cubic kilometres (15 cu mi) Gulf of Anadyr 13 Kuskokwim River Alaska (United States) 1,165 kilometres (724 mi) 120,000 square kilometres (46,000 sq mi) 1,900 cubic metres per second (67,000 cu ft/s) 60 cubic kilometres (14 cu mi) Bering Sea Largest unfragmented river in North America.
Small dams exist on tributaries of Yukon, with which it shares a major delta. 14 Indigirka River Russia (Sakha) 1,726 kilometres (1,072 mi) 360,400 square kilometres (139,200 sq mi) 1,810 cubic metres per second (64,000 cu ft/s) 57 cubic kilometres (14 cu mi) Arctic Ocean Oymyakon, often thought of as the Northern Pole of Cold, located on main stem of river. 15 Great Tenasserim River Burma 300 kilometres (190 mi) 1,788 cubic metres per second (63,100 cu ft/s) 56 cubic kilometres (13 cu mi) Andaman Sea Discharge estimated in absence of streamgauges. 16 Copper River Alaska (United States) 460 kilometres (290 mi) 63,000 square kilometres (24,000 sq mi) 1,700 cubic metres per second (60,000 cu ft/s) 54 cubic kilometres (13 cu mi) Pacific Ocean 17 Laluai River Papua New Guinea (New Britain) 1,612 cubic metres per second (56,900 cu ft/s) 51 cubic kilometres (12 cu mi) Pacific Ocean Hydropower dams proposed at present,^[6] so may not remain on list permanently 18 Stikine River Canada
Alaska (United States) 539 kilometres (335 mi) 52,000 square kilometres (20,000 sq mi) 1,600 cubic metres per second (57,000 cu ft/s) 51 cubic kilometres (12 cu mi) Pacific Ocean 19 Taz River Russia 1,401 kilometres (871 mi) 150,000 square kilometres (58,000 sq mi) 1,540 cubic metres per second (54,000 cu ft/s) 49 cubic kilometres (12 cu mi) Kara Sea 20 Courantyne River Suriname
Guyana 765 kilometres (475 mi) 69,000 square kilometres (27,000 sq mi) 1,500 cubic metres per second (53,000 cu ft/s) 47 cubic kilometres (11 cu mi) Atlantic Ocean 21 Susitna River Alaska (United States) 504 kilometres (313 mi) 63,400 square kilometres (24,500 sq mi) 1,400 cubic metres per second (49,000 cu ft/s) 44 cubic kilometres (11 cu mi) Pacific Ocean Hydropower dams proposed at present, so may not remain on list indefinitely^[7] 22 Thelon River Canada (Nunavut) 900 kilometres (560 mi) 239,332 square kilometres (92,407 sq mi) 1,380 cubic metres per second (49,000 cu ft/s) 44 cubic kilometres (11 cu mi) Chesterfield Inlet 23 Chari River Chad
Cameroon
Central African Republic 949 kilometres (590 mi) 548,747 square kilometres (211,872 sq mi) 1,200 cubic metres per second (42,000 cu ft/s) 38 cubic kilometres (9.1 cu mi) Lake Chad Only dryland river with discharge over 10 cubic kilometres (2.40 cu mi) not affected by dams. 24 Olenyok River Russia (Sakha) 2,270 kilometres (1,410 mi)^[8] 219,300 square kilometres (84,700 sq mi)^[8] 1,090 cubic metres per second (38,000 cu ft/s) 35 cubic kilometres (8.4 cu mi) Arctic Ocean 25 Kamchatka River Russia 758 kilometres (471 mi) 56,300 square kilometres (21,700 sq mi) 1,050 cubic metres per second (37,000 cu ft/s) 33 cubic kilometres (7.9 cu mi) Pacific Ocean