The European Federation, also referred to as the United States of Europe (USE), European State, or Federal Europe, is a hypothetical scenario of European integration leading to the formation of a sovereign superstate, organised as a federation of the member countries of the European Union (EU), as contemplated by political scientists, politicians, geographers, historians, futurologists and fiction writers. At present, while the EU is not a federation, various academic observers regard it as having some of the characteristics of a federal system.

The European Union (EU) is a supranational political and economic union of 27 member states that are located primarily in Europe. The Union has a total area of 4,233,255 km2 (1,634,469 sq mi) and an estimated total population of over 448 million. The EU has often been described as a sui generis political entity combining the characteristics of both a federation and a confederation.