Ynys Castell

Ynys Castell () is a small (1.6

acres The acre is a unit of land area used in the imperial and US customary systems. It is traditionally defined as the area of one chain by one furlong (66 by 660 feet), which is exactly equal to 10 square chains, of a square mile, 4,840 square ya ...

at high tide)

island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island ...

in the

Menai Strait The Menai Strait ( cy, Afon Menai, the "river Menai") is a narrow stretch of shallow tidal water about long, which separates the island of Anglesey from the mainland of Wales. It varies in width from from Fort Belan to Abermenai Point to from ...

which separates

Anglesey Anglesey (; cy, (Ynys) Môn ) is an island off the north-west coast of Wales. It forms a principal area known as the Isle of Anglesey, that includes Holy Island across the narrow Cymyran Strait and some islets and skerries. Anglesey island ...

and mainland

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

. It is an extruding piece of

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the ...

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes o ...

lying to one side of the

Afon Cadnant The Afon Cadnant ( en, River Cadnant) is a small river on Anglesey, North Wales, which drains to the Menai Strait about 1 km north-east of the Menai Suspension Bridge. The river drains a largely agricultural area from Llandegfan to Llansadw ...

estuary. It lies between

Ynys y Bîg Ynys y Bîg is a small private island in the Menai Strait attached to the island of Anglesey (in North Wales) by a wooden bridge. The bridge runs from the grounds of a private house, itself also called Ynys y Bîg, preventing any public access. ...

and

Ynys Gaint Ynys Gaint is a small island in the Menai Strait connected to the town of Menai Bridge on Anglesey by a causeway (which still exists today) and also a concrete bridge erected by Sir William Fison (a previous owner of the island) in the 1930s. ...

. There is a causeway running to the island that is covered at high tide. On the island there is a private house. Ynys Castell means Castle Island in Welsh. Islands of Anglesey Menai Strait Cwm Cadnant {{Anglesey-geo-stub