Tidal island

A tidal island is a piece of land that is connected to the mainland by a natural or man-made causeway that is exposed at low tide and submerged at high tide. Because of the mystique surrounding tidal islands many of them have been sites of religious worship, such as Mont Saint-Michel with its Benedictine Abbey. Tidal islands are also commonly the sites of fortresses because of their natural fortifications.

Tidal island diagram
Diagram of tidal island at low tide and high tide
St Michael's Mount, Cornwall, at high tide, c. 1900
Cramond Island and causeway from air
Cramond Island, Scotland, at high tide: the causeway is submerged, but the anti-boat pylons are still visible.

List of tidal islands


Hong Kong

Republic of China


South Korea


Channel Islands






Grótta in Seltjarnarnes in Capital Region


United Kingdom

Worm's Head (Rhossili)
Worm's Head at the end of Gower, Wales

43 (unbridged) tidal islands can be walked to from the UK mainland.[1]

North America


United States

Bar island 1
Bar Island in Maine, U.S.

Nahant, MA



New Zealand

Rangitoto from Achilles Point
Rangitoto Island forms a backdrop to a wave-cut platform off Achilles Point, Auckland, New Zealand.

See also


  1. ^ Peter Caton (2011). No Boat Required – Exploring Tidal Islands. ISBN 978-1848767-010.
  2. ^ longpointisland.com Archived 2007-09-27 at the Wayback Machine

External links

Bar Island

Bar Island (44°23′54″N 68°12′24″W) is a tidal island across from Bar Harbor on Mount Desert Island, Maine, United States. The uninhabited island forested is mostly in pine and birch trees and the island is now part of Acadia National Park. There are walking trails on the island.

A sand and gravel bar exposed only a couple of hours at low tide connects Bar Island to Bridge Street in Bar Harbor. At low tide visitors often walk across, or park cars on the exposed bar. However, on the island side in front of a locked gate, only a small area fringed with dense sea rose bushes is elevated enough to provide safe parking. Visitors have been known to return from a hike to find their cars submerging and themselves stranded until the tide recedes.The town of Bar Harbor has repeatedly attempted to obtain jurisdiction over this island connected to it by the eponymous bar, but a 1903 court decision confirmed that the distant town of Gouldsboro retains jurisdiction under its 1798 articles of incorporation.

Brough of Birsay Lighthouse

The unmanned Brough of Birsay Lighthouse lighthouse was built in 1925 by David A Stevenson. It is located on the Brough of Birsay, an uninhabited tidal island off the north west coast of Mainland in Orkney, Scotland, in the parish of Birsay.

Burry Holms

Burry Holms (grid reference SS403926) is a small tidal island located at the northern end of the Gower Peninsula, Wales. Its name has no known Welsh-language equivalent (the name Ynys Lanwol previously given here merely meant "tidal island"). 9,000 years ago it was up to 12 miles (19 km) away from the sea and inhabited by nomadic Mesolithic hunters. Flint tools provided the first evidence of their existence in 1919, since when charcoal, charred hazelnut shells, and tools made out of wood and bone have also been found. A 1998 excavation by the National Museums and Galleries of Wales found that Burry Holms was used as a Mesolithic seasonal camp. Iron Age people subsequently built a 5-acre (20,000 m2) hillfort and ditch on the island, while in Medieval times it was home to a monastery.

During spring and summer Burry Holms is covered by flowers such as thrift and sea campion. The island is also popular among collectors of shells.

It reaches a height of 30 metres (98 ft).

Conspiracy Island

Conspiracy Island is a privately owned tidal island situated in the Assonet River off Berkley, Massachusetts.

According to the 2000 census, Conspiracy Island is uninhabited. In very low tides, the island is actually a peninsula, accessible across a sandy stretch of land connecting it to a nearby beach.

A Gazetteer of the State of Massachusetts, published in 1890, describes the history of localities in Massachusetts. In its listing for Berkley, the book states that the island may have received its name from its connection to King Philip, himself the namesake of King Philip's War. Berkley’s history also includes a legend that in 1675 on Conspiracy Island King Phillip formed his confederacy. Also in 1675 Edward Bobbet (Babbitt) returning to his home became the first white man slain by Indians in the area during the King Phillip War.


Cribinau is a small tidal island off the south west coast of the isle of Anglesey in Wales between Porth China and Porth Cwyfan. The island is in Aberffraw Community, about 1.2 miles (2 km) west of Aberffraw village.

The island can be reached on foot at low tide. It is notable for the 13th-century Church in Wales church of St Cwyfan, called in Welsh: eglwys bach y mor ("the little church in the sea") or simply Cwyfan.

Douglas Island

Douglas Island is a tidal island in the U.S. state of Alaska, just west of downtown Juneau and east of Admiralty Island. It is separated from mainland Juneau by the Gastineau Channel.

Eilean Fladday

Eilean Fladday (also Fladda) is a previously populated, tidal island off Raasay, near Skye, Scotland.


Flodaigh is a tidal island lying to the north of Benbecula and south of Grimsay in the Outer Hebrides, Scotland. It is connected to Benbecula by a causeway.

The island is 145 hectares and in 2001 had a population of 11 and 7 in 2011. The census refers to the island by its anglicized name of 'Flodda'.

Grimsay (South East Benbecula)

Grimsay, south east of Benbecula is a tidal island of the Outer Hebrides. It is connected to Benbecula by a causeway which carries the B891. In the 2001 census, Grimsay had a population of 19 and 20 in 2011.An extension to the B891 now connects Grimsay to Eilean na Cille to the south east via a causeway. The road was built at a cost of £1,800 to service the pier at Peter's Port, which was constructed in 1896 at cost of £2,000 - although the anchorage is awkward and should not be used without local knowledge.


Heaste or Heasta is a small settlement on the island of Skye, Scotland. It is located south of Broadford and is in the Scottish council area of Highland.

The tidal island of Eilean Heast lies just off-shore in inner Loch Eishort.


Lampay is an uninhabited tidal island in Loch Dunvegan, off the northwest coast of the Isle of Skye in Scotland.

It is separated from the "mainland" of Skye by a small sound called An Doirneil. It is not far from Claigan. The island doubles in size at low tide, and is really two islands connected by a thin isthmus. It is due south of Isay.

List of islands of Wales

This is a list of islands of Wales, the mainland of which is part of Great Britain, as well as a table of the largest Welsh islands by area. The list includes tidal islands such as Sully Island but not locations such as Shell Island which, though they are termed islands, are peninsulas.


Ornsay is a small tidal island to the east of the Sleat peninsula on the Isle of Skye in the Inner Hebrides of Scotland.

Oronsay, Loch Bracadale

Oronsay (Scottish Gaelic: Orasaigh) is an uninhabited tidal island in Loch Bracadale on the west coast of Skye, Scotland. At low water the island is connected to Ullinish Point on Skye.

The eastern part of the island, which faces Skye, is low-lying grass land, while the western part rises until it reaches several cliffs, up to 70 metres (230 ft) in height.Oronsay is a well known hiking destination.

Ross of Mull

The Ross of Mull (Scottish Gaelic: An Ros Mhuileach) is the largest peninsula of the Isle of Mull, about 28 kilometres (17 mi) long, and makes up the south-western part of the island. It is bounded to the north by Loch Scridain and to the south by the Firth of Lorne. The main villages are Bunessan and Fionnphort, with smaller settlements including Ardtun, Camas, Carsaig, Knockan, Pennyghael and Uisken. Knocknafenaig, Suidhe, and Shiaba are three of the many cleared settlements on the Ross.

Historically the area's main industries consisted of crofting, fishing, kelp, and granite quarries. By 2011 this had shifted with tourism becoming the greatest employer accounting for 29% of employment, while between them farming and fishing made up 15%.The 1886 novel Kidnapped by Robert Louis Stevenson is partially set on the island of Erraid, a tidal island to the south west of the Ross of Mull.

The 1945 film I Know Where I'm Going!, directed by Michael Powell and Emeric Pressburger, was principally shot on Mull, using Carsaig as a headquarters, and references the fictional "Isle of Kiloran", which was based on Colonsay. Other scenes were shot at Duart Castle and Calgary. Also being shot here is The Silent Storm, starring Damian Lewis and Andrea Riseborough.

Soay Beag

Soay Beag (Scottish Gaelic: Sòdhaigh Beag) is a small, uninhabited tidal island in West Loch Tarbert, between the northern and southern parts of Harris. Soay Beag is separated from the southwest coast of North Harris by the Soay Sound. The island is located immediately to the northwest of the larger Soay Mòr, which is accessible on foot at low tide. Soay Beag's highest elevation is 37m (121 feet).

South Mainland

The South Mainland of the Shetland Islands is the southern peninsula of Mainland island. It lies south of Hellister (60° 14′N). The greater southern part of the peninsula belongs to the civil parish of Dunrossness. The rest belongs to the parishes of Lerwick and Tingwall (small part of the latter). St Ninian's Isle is a tidal island off its west coast.

Points of interest include:











Fitful Head

Sumburgh Head

Ynys Llanddwyn

Ynys Llanddwyn or Llanddwyn Island is a small tidal island off the west coast of Anglesey (Welsh: Ynys Môn), northwest Wales. The nearest town is Newborough.

Ynys Lochtyn

Ynys Lochtyn is a tidal island on the coast of Cardigan Bay, located 1.5 miles north east of the village of Llangrannog in the county of Ceredigion, Wales.



This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.