How the European Union grew, 1958–2020
From six founding members to 28, and then the United Kingdom's exit.
Orange shows countries joining at this step, blue shows countries that were already members, and yellow shows a country leaving.
Every step in words
1958: Six founding members
Borders as of 1 January 1958
The Treaty of Rome set up the European Economic Community (EEC), the “Common Market,” among France, West Germany, Italy, Belgium, the Netherlands and Luxembourg. The same six had pooled their coal and steel in 1952.
After two world wars, tying France and Germany's economies together made another war between them almost unthinkable. Trade grew quickly inside the Common Market.
1973: Britain, Ireland and Denmark join
Borders as of 1 January 1973
The United Kingdom, Ireland and Denmark joined. France had blocked Britain twice in the 1960s.
With Britain in, the Community took in most of Western Europe's big economies.
1981: Greece joins
Borders as of 1 January 1981
Greece joined, seven years after its military dictatorship fell.
Membership was a way to lock in democracy, a pattern repeated with Spain and Portugal.
1986: Spain and Portugal join
Borders as of 1 January 1986
Spain and Portugal joined, about ten years after their dictatorships ended.
The same year, the Single European Act set the goal of a single market with free movement of goods, services, money and people by 1992.
1990: Germany reunites
Borders as of 3 October 1990
When East Germany joined West Germany, its land became part of the Community without a new treaty.
A united Germany was the Community's largest country. The Maastricht Treaty (1992) turned the Community into the European Union in 1993 and planned a shared currency, the euro.
1995: Austria, Finland and Sweden join
Borders as of 1 January 1995
Austria, Finland and Sweden, all neutral during the Cold War, joined the new European Union.
With the Cold War over, neutral countries no longer had to stay out.
2004: The big eastern enlargement
Borders as of 1 May 2004
Ten countries joined at once: Poland, Hungary, the Czech Republic, Slovakia, Slovenia, Estonia, Latvia, Lithuania, Malta and Cyprus.
Eight of them had been communist fifteen years before. Joining the EU (and NATO) anchored them in the West, and free movement brought many of their workers to Western Europe.
2007: Bulgaria and Romania join
Borders as of 1 January 2007
Bulgaria and Romania joined, bringing the EU to 27 members.
The EU now reached the Black Sea.
2013: Croatia joins
Borders as of 1 July 2013
Croatia became the 28th member, the second from the former Yugoslavia after Slovenia.
It joined less than twenty years after its war of independence.
2020: Brexit
Borders as of 1 February 2020
The United Kingdom left the EU on 31 January 2020, after a 2016 referendum in which 52% voted to leave.
It was the first time a member left. Arguments over sovereignty, immigration and the EU's power that led to Brexit are part of a wider debate across Europe.
Where the borders come from
- OpenHistoricalMap country boundaries, OpenHistoricalMap contributors. CC0 (public domain).
- Natural Earth coastlines, lakes and countries (1:50m), Natural Earth. Public domain.
- EU member countries and the dates they joined, European Union. Reuse allowed with attribution (European Commission reuse policy).
What to keep in mind
- Borders come from OpenHistoricalMap, an open map of history built by volunteers. Each country's border has a start and end date, and the map shows the ones in force on the date given. Volunteers trace them from old maps and treaties, so small details can be off, and few borders cite a source line by line.
- To keep the map quick to load, borders and coastlines are smoothed, and tiny states (like San Marino or Andorra) may be too small to see. They're still in the list below the map.
- Land with no shape in the dataset for that date is drawn plain, with no border. The larger gaps are named under the map for that step.
- Membership dates are from the EU's own list of member countries. Whole countries are colored, with a few exceptions worth knowing: Greenland (in the Community with Denmark from 1973 until it left in 1985) and the Faroe Islands (never in it) are left plain; in 1958 France's shape includes Algeria, then governed as part of France (independent in 1962); and all of Cyprus is colored from 2004, though EU law is suspended in the north, run by Turkish Cypriots since 1974.
- Crimea is drawn as part of Ukraine on the steps after 1991, including 2020. Russia seized it in 2014, but the UN General Assembly and the EU still recognize it as part of Ukraine.