Newport Castle is a ruined castle in Newport, Wales. It was built in the 14th century, probably by Hugh de Audley, 1st Earl of Gloucester or his son-in-law, Ralph, Earl of Stafford, with the purpose of managing the crossing of the River Usk. The castle was used as administrative offices for the collection of rent and dues from local tenants, and was also a residence and a garrison. In 1402 it was sacked by Owain Glyndŵr. It was in disrepair by 1522, and was taken by Oliver Cromwell's forces during the Civil War. Its use declined further in later centuries. It has been a Grade II* Listed building since 1951.

Newport is a city and county borough in Wales, situated on the River Usk close to its confluence with the Severn Estuary, 12 mi (19 km) northeast of Cardiff. The population grew considerably between the 2011 and the 2021 census, rising from 145,700 to 159,587, the largest growth of any unitary authority in Wales. Newport is the third-largest principal authority with city status in Wales, and sixth most populous overall. Newport became a unitary authority in 1996 and forms part of the Cardiff-Newport metropolitan area, also known as the Cardiff Capital Region.