The Fens is an area of land in the counties of Cambridgeshire (ca. 320,000 acres or 1300 km²) and Lincolnshire in England.
300 years ago, the Fens were similar to the Florida Everglades, a large area of low-lying land. The land started to be drained in the 1640s. Two cuts were made in the Cambridgeshire Fens to join the River Great Ouse to the sea at King's Lynn - the Old Bedford River and the New Bedford River, also known as the Hundred Foot Drain. Both cuts were named after the Fourth Earl of Bedford who, along with some "Gentlemen Adventurers" (venture capitalists), funded the construction.
These days, much of the Fens lies below sea level with the highest point being only a few meters above sea leve, and only sizable river banks and flood defenses stop the land from being reclaimed.
Wisbech is known as the "Capital of the Fens".
The novel The Nine Tailors by Dorothy Sayers is located here.