A kind of low-lying ground, often wet or marshy (noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "fenland" in a sentence
"The river Tern, which flows south from the Weald Moors – an ancient fenland that had been drained by the 18th century – met the Severn at Atcham and backed up across fields into parkland at Attingham."
"The fenland landscape may be flat and dreary; these stories are anything but."
"The 30 fiercely imagined stories in Jon McGregor's collection share an extraordinary topophilia: each bears as its subtitle the name of a fenland town or village, and even in tales that range widely across space and time we never lose touch with the flat Lincolnshire landscape."