Straits and Isthmuses of the World

Blue = straits (narrow waterways between seas), Red = isthmuses (narrow land between seas). Hover markers for names.

Straits — Chokepoints Between Seas

Global Trade Bottlenecks

• Strait of Malacca — 25% of world trade passes through. Narrowest point 2.8 km
• Strait of Hormuz — 20–25% of global oil transits here. Minimum width 39 km
• Bab-el-Mandeb — The only entrance to the Suez Canal route. 26 km wide

Straits That Divide Continents

• Bosphorus — Divides Europe and Asia. Narrowest point 700 m. Istanbul straddles both sides
• Strait of Gibraltar — 14.3 km between Europe and Africa. The Mediterranean's only outlet
• Strait of Dover — 33.3 km between England and France. The Channel Tunnel runs beneath it

Geopolitical Flashpoints

• Taiwan Strait — 180 km between mainland China and the island of Taiwan
• Korea Strait — 200 km between the Korean Peninsula and Japan. Tsushima Island sits in the middle. Site of the 1905 Battle of Tsushima

Extreme Straits

• Drake Passage — The world's widest strait (800 km). Between South America and Antarctica. Notoriously rough seas
• Strait of Magellan — First navigated by Magellan in 1520. The key Pacific route before the Panama Canal

Southeast Asian Bottlenecks

• Singapore Strait — Exit of the Malacca Strait. 16 km wide
• Sunda Strait — Between Java and Sumatra. Site of the 1883 Krakatoa eruption
• Lombok Strait — Sits on Wallace's Line (the biogeographic boundary between Asian and Australasian fauna)

Isthmuses — Narrow Land Between Two Seas

Isthmuses Cut by Canals

• Isthmus of Panama — 50 km wide. Panama Canal opened 1914. When this land rose ~3 million years ago, it split Atlantic and Pacific currents and triggered an ice age
• Isthmus of Suez — 125 km wide. Suez Canal opened 1869. Eliminated the need to sail around Africa
• Isthmus of Corinth — 6.3 km wide. Corinth Canal completed 1893. Ancient Greeks dragged ships overland on a paved trackway

Isthmuses Not Yet Cut

• Isthmus of Kra — Southern Thailand, 44 km wide. A canal bypassing the Strait of Malacca has been discussed for centuries but never built
• Isthmus of Tehuantepec — The narrowest point of Mexico (200 km). A major trade route before the Panama Canal

Military Chokepoints

• Isthmus of Perekop — Connects the Crimean Peninsula to the mainland (sovereignty disputed). 5–7 km wide. Fortified since antiquity
• Karelian Isthmus — Between Finland and Russia. Site of the fierce Winter War (1939–1940)