Werrington (Cornish: Trewolvredow) is a civil parish and former manor now in Cornwall, England. Prior to boundary changes it straddled the Tamar and lay within the county of Devon.The portion on the west side was transferred to Cornwall in 1966. It is situated 1 mile to the west of the River Tamar, the traditional boundary between Devon and Cornwall, and 2 miles north of Launceston.