Baltic Sea

Introduction
Physical features
- Physiography
- Climate
- Hydrology
- Coastal features
Economic aspects
Study and exploration

References & Edit History Related Topics

Images & Videos

Map showing the physical features, major cities, and national boundaries around the Baltic Sea, North Sea, and English Channel regions of northern and western Europe. The map highlights coastal countries including the United Kingdom, Norway, Denmark, Germany, the Netherlands, Belgium, France, Sweden, Finland, Estonia, Latvia, Lithuania, Poland, and Russia, with sea depths indicated and key islands, peninsulas, and underwater trenches labeled.

The East Bridge of the Great Belt Fixed Link, a large suspension bridge with tall towers and cables, spans across the water between Zealand and Funen in Denmark.

Steep white chalk cliffs rise sharply with sparse trees along the top edge on the eastern coast of Mon island, Denmark.

Chalk cliffs at Stubbenkammer promontory on the island of Rügen, Ger.

Ostseebad Ahrenshoop, Ger., on the Baltic Sea.

The Marienkirche with its twin green spires rises above the central market square, surrounded by red-roofed buildings in Lubeck, Schleswig-Holstein, Germany.

The Kiel Canal, running from the mouth of the Elbe River to the Baltic Sea, Kiel, Ger.

At a Glance

Baltic Sea summary

Quizzes

water glass on white background. (drink; clear; clean water; liquid)

Water and its Varying Forms

wave. ocean. Cresting ocean wave. Large sea waves. storm, hurricane, tropical cyclone

All About Oceans and Seas Quiz

Related Questions

How can fertilizer runoff cause eutrophication in the Baltic Sea?
How deep is Landsort Deep in the Baltic Sea?
How did Vikings open the Baltic Sea to trade?
How did glaciers shape the coast of Denmark along the Baltic Sea?
How did melting ice sheets help form the Baltic Sea?
How did sand dunes and shingle bars form lagoons along the German and Polish Baltic coasts?
How did the Hanseatic League protect merchants from pirates and robbers?
How did the Kiel Canal change travel and trade between the Baltic Sea and North Sea?
How large is the Baltic Sea?
How long is the Baltic Sea from eastern Denmark to southern Finland?
How were the skerry islands along the Swedish and Finnish coasts formed?
What goods did Hanseatic merchants transport across the Baltic Sea?
What role do the Kattegat and Skagerrak play in connecting the Baltic Sea to the North Sea?
What types of cargo are transported through the Baltic Sea?
What was the purpose of the Helsinki Convention on protecting the Baltic Sea?
What were the Yoldia Sea and Ancylus Lake?
Where are the chalk cliffs on the Baltic island of Rügen?
Where are the Åland Islands located?
Where is the Baltic Sea located in Europe?
Where is the Curonian Spit located?
Where is the deepest point in the Baltic Sea?
Which Baltic Sea resort towns are popular tourist destinations?
Which countries border the Baltic Sea?
Which countries border the Gulf of Bothnia?
Which countries border the Gulf of Finland?
Which fish are commonly caught in the Baltic Sea?
Which islands are located in the Baltic Sea?
Which river flows into the Baltic Sea near the Polish city of Gdańsk?
Which rivers bring large amounts of freshwater into the Baltic Sea?
Why are large ships restricted in The Sound between Denmark and Sweden?
Why are parts of the land around the Gulf of Bothnia still rising?
Why are the coasts of Sweden and Finland rocky and irregular?
Why did Dutch ships become important in Baltic Sea trade?
Why did Lübeck become a leading Hanseatic trading city?
Why did environmental concerns affect plans for an undersea natural-gas pipeline in the Baltic Sea?
Why does pack ice form in the Gulf of Bothnia during many winters?
Why does the Baltic Sea have very weak tides and tidal currents?
Why is salinity highest in the western Baltic Sea?
Why is the Baltic Sea considered the world’s largest area of brackish water?
Why is the Baltic Sea especially vulnerable to pollution?
Why is the Baltic Sea less salty than the Atlantic Ocean?
Why is the water near the head of the Gulf of Bothnia nearly fresh?
What islands make up Guadeloupe?
What is the climate in Guadeloupe?
Is the Black Sea freshwater or saltwater?
What’s notable about oxygen levels in the Black Sea?
How salty is the Caspian Sea?
What is the Panama Canal?
Why is the Panama Canal important?
How was the Panama Canal made?
Why does the Panama Canal need locks?
Who built the Panama Canal?

Geography & Travel Physical Geography of Water Oceans & Seas

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External Websites

World Wide Fund For Nature - The Baltic Sea, Europe
American Association for the Advancement of Science - Science Advances - The Baltic Sea as a time machine for the future coastal ocean

Britannica Websites

Articles from Britannica Encyclopedias for elementary and high school students.

Baltic Sea - Children's Encyclopedia (Ages 8-11)
Baltic Sea - Student Encyclopedia (Ages 11 and up)

Baltic Sea

sea, Europe

Also known as: Østersøen, Östersjön, Baltiyskoye More, Itämeri, Morze Bałtyckie, Ostsee(Show More)

Written by

Alastair Dougal Couper

Professor of Maritime Studies, University of Wales College of Cardiff. Editor of The Times Atlas and Encyclopaedia of the Sea.

Alastair Dougal CouperAll

Fact-checked by

Britannica Editors

Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....

Britannica Editors

Last updated

Nov. 12, 2026 •History

Baltic Sea, arm of the North Atlantic Ocean, extending northward from the latitude of southern Denmark almost to the Arctic Circle and separating the Scandinavian Peninsula from the rest of continental Europe. The largest expanse of brackish water in the world, the semienclosed and relatively shallow Baltic Sea is of great interest to scientists, while to historians it represents the economic core of the Hanseatic League, the great medieval trading group of northern European ports....

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