Isthmus

An isthmus is a narrow piece of land that connects two larger areas across water. Without these special strips of land, the areas would be separated by water. The word "isthmus" comes from Ancient Greek, where it meant "neck."

A type of isthmus called a tombolo is formed from a spit or bar. A strait is like an isthmus but is made of water—it is a narrow stretch of sea between two land areas that connects larger bodies of water. Isthms are important because they help people, animals, and plants move between places that would otherwise be too far apart.

Isthmus vs land bridge vs peninsula

An isthmus and a land bridge are similar ideas, but an isthmus has a broader meaning. A land bridge is a special type of isthmus that connects Earth's major landmasses. The term land bridge is often used in biogeology to talk about old land connections between continents that helped people and animals move around, like Beringia and Doggerland.

An isthmus connects two larger pieces of land, while a peninsula sticks out from one larger piece of land and is surrounded by water on most sides. Some isthmuses have canals, like the Panama Canal, that cut through them from one side to the other. These canals are made by people, unlike natural waterways called straits.

Major isthmuses

Some important narrow pieces of land that connect larger areas are:

• Karelian Isthmus in Europe
• Kra Isthmus in Mainland Southeast Asia
• Bird's Neck Isthmus in Western New Guinea
• Isthmus of Tehuantepec in Middle America
• Isthmus of Perekop in Ukraine
• Isthmus of Panama in Middle America
• Isthmus of Suez between North Africa and Western Asia

Historically important ones include:

• Isthmus of Catanzaro in Italy
• Isthmus of Corinth in Greece

The cities of Auckland, Madison, Manila, and Seattle are located on these narrow lands.

Canals

Canals are often built across narrow pieces of land called isthmuses. These canals provide a shorter route for ships to travel between large bodies of water.

For example:

• The Panama Canal crosses the Isthmus of Panama, connecting the Atlantic and Pacific Oceans
• The Suez Canal connects the Mediterranean Sea (part of the Atlantic Ocean) and the Red Sea (part of the Indian Ocean), cutting across the western side of the Isthmus of Suez, formed by the Sinai Peninsula
• The Crinan Canal crosses the isthmus between Loch Crinan and Loch Gilp, which connects the Kintyre peninsula with the rest of Scotland
• The Welland Canal in the Niagara Peninsula (technically an isthmus); it connects Lake Ontario to Lake Erie
• The Corinth Canal connects the Gulf of Corinth in the Ionian Sea with the Saronic Gulf in the Aegean Sea
• The Lake Washington Ship Canal connects the Puget Sound to Lake Washington in Seattle via Lake Union