thumb|350px|Stanley's route is depicted by the solid black line.

The Kasai River (, ; called Cassai in Angolan Portuguese) is a left bank tributary of the Congo River, located in Central Africa.

| label_type = Period

| data_type = Average discharge (m<sup>3</sup>/s)

| bar_width = 14

| width_units = em

| data_max =11,320

| label1=2012–2016

| data1=9,000

| label2=1948–2012

| data2=10,457

| label3=1950–1959

| data3=11,318

{| class="wikitable mw-collapsible mw-collapsed" style="text-align:center;"

|+Water discharge of the Kasai River at the Lediba () and Kutu-Moke () gauging station.

|-

! rowspan="2" |Year

! rowspan="71" |

!Lediba

!

!Kutu-

Moke

|-

! colspan="3" |Average discharge

(m³/s)

|-

|2016

|9,350

| rowspan="69" |

|

|-

|2015

|8,090

|

|-

|2014

|9,040

|

|-

|2013

|9,520

|

|-

|2012

|8,870

|6,800

|-

|2011

|7,940

|6,093

|-

|2010

|7,320

|5,614

|-

|2009

|8,820

|6,764

|-

|2008

|10,400

|7,976

|-

|2007

|13,180

|10,110

|-

|2006

|10,740

|8,236

|-

|2005

|9,017

|6,917

|-

|2004

|8,130

|6,235

|-

|2003

|11,520

|8,837

|-

|2002

|11,150

|8,552

|-

|2001

|9,290

|7,125

|-

|2000

|8,310

|6,496

|-

|1999

|7,030

|5,463

|-

|1998

|7,010

|5,480

|-

|1997

|9,800

|7,659

|-

|1996

|8,950

|7,000

|-

|1995

|7,620

|5,960

|-

|1994

|7,430

|5,810

|-

|1993

|8,580

|6,705

|-

|1992

|7,790

|6,089

|-

|1991

|10,410

|8,136

|-

|1990

|11,150

|8,717

|-

|1989

|12,810

|9,988

|-

|1988

|11,450

|8,953

|-

|1987

|11,120

|8,694

|-

|1986

|9,980

|7,804

|-

|1985

|9,550

|7,463

|-

|1984

|8,800

|6,879

|-

|1983

|10,340

|8,084

|-

|1982

|10,100

|7,897

|-

|1981

|9,500

|7,427

|-

|1980

|9,230

|7,213

|-

|1979

|11,710

|9,153

|-

|1978

|10,730

|8,385

|-

|1977

|12,450

|9,731

|-

|1976

|11,760

|9,194

|-

|1975

|10,720

|8,383

|-

|1974

|10,080

|7,878

|-

|1973

|9,970

|7,796

|-

|1972

|10,540

|8,236

|-

|1971

|11,360

|8,880

|-

|1970

|12,040

|9,232

|-

|1969

|13,020

|9,986

|-

|1968

|13,100

|10,050

|-

|1967

|11,510

|8,832

|-

|1966

|12,340

|9,466

|-

|1965

|10,970

|8,417

|-

|1964

|11,950

|9,167

|-

|1963

|11,960

|9,173

|-

|1962

|13,510

|10,360

|-

|1961

|12,440

|9,543

|-

|1960

|11,430

|8,764

|-

|1959

|9,960

|7,638

|-

|1958

|9,850

|7,552

|-

|1957

|11,810

|9,060

|-

|1956

|11,580

|8,882

|-

|1955

|11,360

|8,717

|-

|1954

|11,390

|8,735

|-

|1953

|10,220

|7,837

|-

|1952

|10,490

|8,646

|-

|1951

|11,260

|8,640

|-

|1950

|11,240

|8,619

|-

|1949

|11,560

|8,870

|-

|1948

|11,360

|8,716

|-

| colspan="5" |

|-

| colspan="5" |Notes:

Average minimum and maximum discharge: Lediba 5,000–20,000 m³/s (1932–1959), Kutu-Moke 4,400–11,600 m³/s (1932–1959)

|-

| colspan="5" |Source:

|}

Exploration

Henry Morton Stanley reached the confluence on 9 March 1877, calling the river Nkutu, a "powerful and deep river", but recognizing it as originating from David Livingstone's Kwango.

Tributaries

The Kasai's main tributaries upstream from the confluence with the Congo:

  • Map of the Kasai River basin at Water Resources eAtlas