Newport Castle is a ruined castle in Newport, South 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.