The River Witham is a river, entirely in Lincolnshire, in the east of England. It rises south of Grantham, passes Lincoln and at Boston, flows into The Haven, a tidal arm of The Wash.

Tributaries of the River Witham:

• Foston Beck
• River Brant
• Fossdyke Navigation, a canalization of the lower River Till.
• Barlings Eau
• River Bain
• Kyme Eau, the fenland part of the River Slea

The following flow into The Haven.

• South Forty Foot Drain
• Maud Foster Drain
• Hobhole Drain

See also

• Rivers of the United Kingdom