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
Holy Island, Anglesey Holy Island, Anglesey Holy Island (, 'the island of (Saint) Cybi') is an island () on the western side of the larger Isle of Anglesey, Wales, from which it is separated by a narrow, winding channel. It is called "Holy" because of the high concentration of standing stones, burial chambers, and other religious sites on the small island. The alternative and historic name of the island is Holyhead Island. According to the 2011 UK Census, the population was 13,659, of which 11,431 (84%) lived in the largest town, Holyhead. Irish pirates invaded Anglesey following the end of Roman rule in