The Castlereagh Memorial Clock was built in 1874 to celebrate the 21st birthday of Charles Stewart Vane-Tempest, the eldest son of the Fifth Marquess of Londonderry. Plas Machynlleth was the family home. The height of this impressive clock tower is seventy-eight feet and it is made of Tremadoc rock and Mansfield red sandstone. It stands on the site of the old Town Hall near the junction with Maengwyn Street.
