Mynydd y Dref (Welsh : Mountain of the Town) or Conwy Mountain is a hilly area to the west of the town of Conwy, in North Wales. To the north it overlooks the sea of Conwy Bay, and to the south lie the foothills of the Carneddau range of mountains, of which it forms a part. Mynydd y Dref is the remains of an ancient volcano that erupted about 450 million years ago.