Ruthin (Welsh: Rhuthun), is the county town of Denbighshire in north Wales. Located around a hill in the southern part of the Vale of Clwyd - the older part of the town, the castle and Saint Peter's Square are located on top of the hill, while many newer parts of the town are on the floodplain of the River Clwyd (which became apparent on several occasions in the late 1990s -- new flood control works costing £3 million were inaugurated in autumn 2003). The name 'Ruthin' comes from the Welsh words rhudd (red) and din (fort), and refers to the colour of the new red sandstone which forms the geologic basis of the area, and from which the castle was constructed in 1277-1284. The original name of Rhuthun was 'Castell Coch yng Ngwern-fôr' (red castle in the sea-swamps).