The Isle of Sheppey is an island off the northern coast of Kent, England in the Thames Estuary, some to the east of London. It has an area of . The island forms part of the local government district of Swale. Sheppey is derived from the ancient Saxon "Sceapige", meaning isle of sheep, and even today the extensive marshes which make up a considerable proportion of the island provide grazing for large flocks of sheep.