Isca, variously specified as Isca Augusta or Isca Silurum, was the site of a Roman legionary fortress and settlement or vicus, the remains of which lie beneath parts of the present-day suburban town of Caerleon in the north of the city of Newport in South Wales. The site includes Caerleon Amphitheatre and is protected by Cadw.

Caerleon is a town and community in Newport, Wales. Situated on the River Usk, it lies 5 miles (8 km) northeast of Newport city centre, and 5.5 miles (9 km) southeast of Cwmbran. Caerleon is of archaeological importance, being the site of a notable Roman legionary fortress, Isca Augusta, and an Iron Age hillfort. Close to the remains of Isca Augusta are the National Roman Legion Museum and the Roman Baths Museum. The town also has strong historical and literary associations: Geoffrey of Monmouth elevated the significance of Caerleon as a major centre of British history in his Historia Regum Britanniae, and Alfred Lord Tennyson wrote Idylls of the King (1859–1885) while staying in Caerleon.