Chatteris /ˈtʃætɛrɪs/ is a market town and civil parish in the Fenland district of Cambridgeshire, England, situated in The Fens between Huntingdon, March and Ely. The town is in the North East Cambridgeshire parliamentary constituency. Following the draining of the Fens, beginning in the 17th century and completed in the 19th century, the town's economy has been based on agriculture and related industry. Due to its proximity to Cambridge, Huntingdon and Peterborough, the town has emerged as a commuter town. The town had a population of 11,011 at the time of the United Kingdom Census 2021.