River Great Ouse
|River Great Ouse|
|Counties||Northamptonshire, Buckinghamshire, Bedfordshire, Cambridgeshire, Norfolk|
|- location||Syresham, South Northamptonshire, Northamptonshire, England|
|- elevation||150 m (490 ft)|
|- location||King's Lynn, United Kingdom|
|- elevation||0 m (0 ft)|
|Length||230 km (143 mi)|
|Basin size||8,380 km2 (3,240 sq mi)|
|- location||Denver Sluice  Catchment area 3430 km2|
|- average||15.8 m3/s (560 cu ft/s)Catchment area 3430 km2|
Its course is 143 miles (230 km), mostly flowing north and east. It is the fifth longest river in the United Kingdom. The Great Ouse was important for commercial navigation, and for draining the low-lying region through which it flows.
Its best-known tributary is the Cam, which runs through Cambridge. Its lower course passes through drained wetlands and fens. It has been extensively modified to relieve flooding and provide a better route for barge traffic. It now enters the Wash after passing through the port of King's Lynn.