North Stack North Stack North Stack (Welsh: Ynys Arw, meaning "rugged island") is a small island situated just off Holy Island on the north-west coast of Anglesey. North Stack can also refer to the headland opposite the island. This is the site of a redundant fog warning station, comprising a number of buildings, including the Trinity House Magazine, built in 1861, where shells for the warning cannon were stored. These buildings now house a bird watching observatory, giving a view of South Stack lighthouse across Gogarth Bay, and the studio of artist Philippa Jacobs. The Precambrian quartzite cliffs of this headland, including
North Wales defined as the region east of the River Conwy and west of the River Dee; and Ynys Môn (or Anglesey), a large island off the north coast. The division with the rest of Wales is arbitrary and depends on the particular use being made. For example, the boundary of North Wales Police differs from the boundary of the North Wales area of the Natural Resources Wales and the North Wales Regional Transport Consortium ("Taith"). The historic boundary follows the pre-1996 county boundaries of Merionethshire and Denbighshire which in turn closely follows the geographic features of the river Dovey to Aran