An isthmus is a thin strip of land that connects two larger land masses. It has water on both of its sides and is sometimes a tombolo, which is formed from deposits such as sand, gravel, or silt. A tombolo usually connects an island to the mainland.
Worldwide Isthmus Examples
Africa, Central America, and South America
- Isthmus of Mansheya connects the island of Pharos to the mainland and Alexandria.
- The Isthmus of Panama is a famous isthmus in Central America because of the Panama Canal which was built through it. It links Costa Rica and South America and is between the Caribbean Sea and the Pacific Ocean.
- Isthmus of Rivas is in Nicaragua and has the Pacific Ocean on one side and Lake Nicaragua on the other.
- Isthmus of Tehuantepec connects Mexico with the Yucatan and Central Mexico. It is bordered by the Gulf of Mexico and the Pacific Ocean.
- In Argentina, the Istmo Carlos Ameghino links Peninsula Buckets and the Province of the Chubut and is bordered by Gulfo Nuevo (New Gulf) and Golfo San Jose.
- In Argentina, the Quetrihué Isthmus is in Nahuel Huapi Lake.
- The Isthmus of East Falkland unites the two land masses that comprise the largest island in the Falklands.
- In Chili, the Ofqui Isthmus connects the Chilean mainland with the Taitao Peninsula.
- Also in Chili, the Isthmus of Muñoz Gamero unites the Muñoz Gamero Peninsula with the Patagonia mainland.
- Another in Chili is the Isthmus of Brunswick Peninsula.
- The Isthmus of Médanos is in Venezuela and links the Paraguana Peninsula and the mainland.
- Isthmus of Avalon unites the Avalon Peninsula to the mainland of Newfoundland.
- Isthmus of Chignecto links Nova Scotia to North America and Canada.
- The Isthmus of the Sechelt Peninsula separates the Sechelt Inlet from the Strait of Georgia.
- Isthmus of Saint Pierre and Miquelon connects Langlade Island with the island of Miquelon.
- The Isthmus of Summerside unites the western portion of Prince Edward Island with the rest of the island.
- Madison Isthmus is in Madison, Wisconsin and links Lake Mendota and Lake Monona.
- Seattle, Washington is located on an isthmus between Puget Sound and Lake Washington.
- Maui, Hawaii has an isthmus between two volcanic masses.
- Coronado, California is located on a peninsula that is connected to the mainland by an isthmus called the Silver Strand.
- Catalina Isthmus is between the small western region of Santa Catalina Island, California and its larger eastern area.
- Isthmus of Nahant connects Nahant, Massachusetts to Massachusetts.
- Isthmus of Olympia, Washington links East Olympia to West Olympia and separates Budd Inlet (part of Puget Sound) and Capitol Lake.
Asia and Russia
- The Isthmus of Suez in Egypt joins Africa and Asia and is the location of the Suez Canal.
- Isthmus of Kra links the Malay Peninsula and the mainland of Asia.
- Isthmus of Kushimoto in Japan joins Cape Shiono-Misaki and Honshū.
- Part of Quezon Province, in Luzon, Philippines unites the mainland of Luzon with the Bicol Peninsula.
- Adam's Bridge, or Rama’s Bridge, connects Sri Lanka and India.
- In Russia, Karelian Isthmus is found between Lake Ladoga and the Gulf of Finland (the Baltic Sea).
- In Russia, the Olonets Isthmus is between Lake Ladoga and Lake Onega.
- Also in Russia, Onega Isthmus lies between Lake Onega and the White Sea.
- Isthmus of Perekop connects the Peninsula of Crimea and the Ukraine Mainland.
- Isthmus of Westfjords peninsula unites the peninsula with the Iceland mainland.
- Isthmus of Corinth joins the Peloponnese Peninsula with Greece.
- Isthmus of Potidea links the Kassandra Peninsula with Greece.
- Isthmus of Gibraltar joins Gibraltar and Spain.
- La Coupée isthmus unites Great Sark and Little Sark.
- In the Shetland Islands, the Mavis Grind isthmus connects Northmavine and the rest of the Shetland Mainland and is bordered by the Atlantic Ocean and the North Sea.
Australia and New Zealand
- Auckland isthmus links the Northland Peninsula and the rest of New Zealand's North Island.
- The Rongotai isthmus in Wellington, New Zealand is between the Miramar Peninsula and the two suburbs of Kilbirnie and Lyall Bay.
- The Neck in Bruny Island, Tasmania joins North and South Bruny.
- Eaglehawk Neck connects mainland Tasmania with the Tasman Peninsula.
- The Taillefer Isthmus is located in Western Australia.
- East Bay Neck is located in Tasmania.
There are many isthmus examples throughout the world. Although some are made of land and others of more granular particles such as sand, what they all have in common is water on both sides.