Mamucium, also known as Mancunium, was a fort in the Roman province of Britannia. The remains of the fort are protected as a Scheduled Ancient Monument, and are located within the Castlefield area of the City of Manchester, in North West England (). Founded c. AD 79, Mamucium was garrisoned by a cohort of auxiliary soldiers and guarded the road running from Chester to York. A vicus, or civilian settlement made up of traders and the families of the soldiers, grew outside the fort and was an area of industrial activity.