Hunnum (also known as Onnum, and with the modern name of Halton Chesters) was a Roman fort north of the modern-day village of Halton, Northumberland in North East England. The Latinized Brittonic name “Onnum” may mean "Stream/Water", "Ash (tree)", or “Rock”; if it means "Stream", it may be a reference to the Fence Burn, where a stream touches the line of Hadrian's Wall,[2] but if it means "Rock", it may refer to Down Hill situated to the east of it.[citation needed] It was the fifth fort on Hadrian's Wall, after Segedunum (Wallsend), Pons Aelius (Newcastle), Condercum and Vindobala. It is situated about seven and a half miles west of Vindobala, and is two and a half miles north of Corstopitum. The site of the fort is bisected by the B6318 Military Road, which runs along the route of the wall at that point.