Isthmus

The sandy isthmus or tombolo connecting North and South Bruny Island in Tasmania, Australia

An isthmus (pronunciation: /ˈɪsθməs/ or /ˈɪsməs/; plural: isthmuses; from Ancient Greek: ἰσθμός isthmos "neck") is a narrow piece of land connecting two larger areas across an expanse of water that otherwise separates them.^[1] A tombolo is an isthmus that consists of a spit or bar, and a strait is the sea counterpart of an isthmus.

Canals are often built across isthmuses, where they may be a particularly advantageous short cut for marine transport. For example, the Panama Canal crosses the Isthmus of Panama, connecting the North Atlantic and Pacific Oceans; the Suez Canal connects the Mediterranean Sea and the Indian Ocean, cutting across the western side of the Isthmus of Suez, formed by the Sinai Peninsula; and the Crinan Canal crosses the isthmus between Loch Crinan and Loch Gilp, which connects the Kintyre peninsula with the rest of Scotland.

See also

• Land bridge
• List of isthmuses
• List of straits

Notes

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Coastal geography
Landforms	Anchialine pool Archipelago Atoll Avulsion Ayre Barrier island Bay Baymouth bar Bight Bodden Brackish marsh Cape Channel Cliff Coast Coastal plain Coastal waterfall Continental margin Continental shelf Coral reef Cove Dune cliff-top Estuary Firth Fjard Fjord Freshwater marsh Fundus Gat Geo Gulf Gut Headland Inlet Intertidal wetland Island Islet Isthmus Lagoon Machair Marine terrace Mega delta Mouth bar Mudflat Natural arch Peninsula Reef Regressive delta Ria River delta Salt marsh Shoal Shore Skerry Sound Spit Stack Strait Strand plain Submarine canyon Tidal island Tidal marsh Tide pool Tied island Tombolo Windwatt
Beaches	Beach cusps Beach evolution Coastal morphodynamics Beach ridge Beachrock Pocket beach Raised beach Recession Shell beach Shingle beach Storm beach Wash margin
Processes	Blowhole Cliffed coast Coastal biogeomorphology Coastal erosion Concordant coastline Current Cuspate foreland Discordant coastline Emergent coastline Feeder bluff Fetch Flat coast Graded shoreline Headlands and bays Ingression coast Large-scale coastal behaviour Longshore drift Marine regression Marine transgression Raised shoreline Rip current Rocky shore Sea cave Sea foam Shoal Steep coast Submergent coastline Surf break Surf zone Surge channel Swash Undertow Volcanic arc Wave-cut platform Wave shoaling Wind wave Wrack zone
Management	Accretion Coastal management Integrated coastal zone management Submersion
Related	Bulkhead line Grain size boulder clay cobble granule pebble sand shingle silt Intertidal zone Littoral zone Physical oceanography Region of freshwater influence
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