Alternative History
Intermarium
Federation of Intermariner Socialist States
Timeline: Triangles and Crosses
Preceded by 1949–1994 Succeeded by
Flag of the Intermarium (Fascist Empire) Flag of Belarus (1918, 1991–1995)
Flag of Lithuania
Flag of Poland
Flag of Ruthenia (TaC)
Flag Coat of Arms
Flag
(1952–1994)
Coat of arms
(1952–1994)
Location of Intermarium
Localization of the Intermarium.
Anthem "Mazurek Dąbrowskiego
("Dąbrowski's Mazurka")"
Capital
(and largest city)
Warsaw
Other cities Vilnius
Gdańsk
Kraków
Language Polish (de facto)
Religion Secular state
Demonym Intermariner
Government Federal Marxist–Spartacist one-party socialist republic
  Legislature Sejm
Chairman of the Council of State Bolesław Bierut (1952–1956)
Józef Cyrankiewicz (1956–1989)
Algirdas Brazauskas (1989–1994)
Premier E. Osóbka-Morawski (1944–1947; first)
Mykolas Burokevičius (1992–1994; last)
Area 492,013 km²
Population 45,155,325 (est. 1989) 
Currency Intermarian złoty (zł)

The Federation of Intermariner Socialist States, commonly known as the Intermarium, was a federal socialist state in Eastern Europe and predecessor to modern states of Belarus, Lithuania, Poland and Ruthenia. With a population of approximately 45 million inhabitants near the end of its existence, it was the most populous communist and Eastern Bloc country in Europe after Germany.

The country would come to a collapse with the death of Józef Cyrankiewicz, with the increase of unemployment and inflation, and rising ethnic nationalism. Efforts to transition back to a democracy failed, and Belarus and Lithuania called for secession. The federation formally broke up on 1994, with the start of the Intermariner Wars.