Anglesey

Anglesey (/ˈæŋɡəlsi/ ANG-gəl-see; Welsh: Ynys Môn [ˈənɨs ˈmoːn]) is an island off the north-west coast of Wales. It forms the bulk of the county known as the Isle of Anglesey, which also includes Holy Island (Ynys Gybi) and some islets and skerries. The county borders Gwynedd across the Menai Strait to the southeast, and is otherwise surrounded by the Irish Sea. Holyhead is the largest town, and the administrative centre is Llangefni.

The Isle of Anglesey has an area of 275 square miles (712 km²) and had a population of 69,097 in 2024. After Holyhead, located on Holy Island, the largest settlements are Llangefni in the centre of Anglesey and Amlwch on the northern coast. The economy of the county is mostly based on agriculture, energy, and tourism, the latter especially on the coast. Holyhead is also a major ferry port for Dublin, Ireland. The county has the second-highest percentage of Welsh speakers in Wales, at 57.2%, and is considered a heartland of the language. The Isle of Anglesey is part of the preserved county of Gwynedd.

The island of Anglesey, at 261 square miles (676 km²), is the largest in Wales and the Irish Sea and the seventh largest in Britain. The northern and eastern coasts of the island are rugged, and the southern and western coasts are generally gentler; the interior is gently undulating. In the north of the island is Llyn Alaw, a reservoir with an area of 1.4 square miles (4 km²). Holy Island, located off the east coast of Anglesey, has a similar landscape, with a rugged north and west coast and beaches to the east and south. The two larger islands are surrounded by smaller islands; several, including South Stack and Puffin Island, are home to seabird colonies. Large parts of the county's coastline have been designated an Area of Outstanding Natural Beauty.

The county has many prehistoric monuments, such as Bryn Celli Ddu burial chamber. The medieval House of Aberffraw, which ruled the Kingdom of Gwynedd until 1283, originated on Anglesey and maintained courts on the island at (llysoedd) at Aberffraw and Rhosyr. After the Conquest of Wales by Edward I, Beaumaris Castle was constructed at the south-eastern corner of Anglesey; today it is part of the Castles and Town Walls of King Edward in Gwynedd World Heritage Site. During the nineteenth century the Menai Strait to the mainland was spanned by two bridges: the Menai Suspension Bridge, designed by Thomas Telford in 1826, and the Britannia Bridge, originally designed by Robert Stephenson in 1850.

The English name for Anglesey might be derived from the Old Norse, either Ǫngullsey "Hook Island" or Ǫnglisey "Ǫngli's Island". No record of such an Ǫngli survives, but the place name was used by Viking raiders as early as the 10th century and later adopted by the Normans during their invasions of Gwynedd. The traditional folk etymology reading the name as the "Island of the Angles (English)" may account for its Norman use but has no merit; the Angles' name itself is probably cognate with the shape of the Angeln peninsula. All of them ultimately derive from the proposed Proto-Indo-European root *ank- ("to flex, bend, angle"). Throughout the 18th and 19th centuries and into the 20th, it was usually spelt Anglesea in documents, a spelling that is still occasionally used today.

Ynys Môn, the island and county's Welsh name, first appeared in the Latin Mona of various Roman sources. It was likewise known to the Saxons as Monez. The Brittonic original was in the past taken to have meant "Island of the Cow".

The name is probably cognate with the Gaelic name of the Isle of Man, Mannin (Manaw in Welsh), usually derived from a Celtic word for 'mountain' (reflected in Welsh mynydd, Breton menez and Scottish Gaelic monadh), from a Proto-Celtic *moniyos.

Poetic names for the island of Anglesey include the Old Welsh Ynys Dywyll (Shady or Dark Isle) for its former groves and Ynys y Cedairn (Isle of the Brave) for its royal courts; Gerald of Wales' Môn Mam Cymru ("Môn, Mother of Wales") for its agricultural productivity; and Y fêl Ynys (Honey Isle).