United States Armed Forces in Europe Leagues
Among the earliest verifiable American Football Leagues or Associations in Europe are the American Expeditionary Force Football League of WWI which was played in France at the conclusion of the War. There was a European Theater of Operations Football Championship (WWII) in Northern Ireland in 1942, which spread to England and Wales in 1943-1944. Following WWII, the United States found itself almost immediately in a War with Communist Russia, and American Football Leagues were set up in the United Kingdom, Germany, France, Italy, Spain & Greece (The United States Air Force in Europe – USAFE – Football League & United States ARmy EURope Football League – USAREUR) which ran right to the end of the Cold War. One USAREUR League, the Northern Italian League, became the genesis of a National League in Italy featuring Homegrown teams.

Picture Credit: [9] Britball Now (2019) USAFE Final 1952 (Wembley) [Internet] Available http://www.britballnow.co.uk/_Media/1952-usaf-final-wembley_med.jpeg [Accessed 8 November 2019]
After World War II and as the Cold War set in, the United States Air Force in Europe set up a Football Championship with three Conferences: United Kingdom, Continental (France and Germany) and Mediteranean (Italy, Spain and Greece) Sports Conferences. There was also a smaller USAREUR (United States Army in Europe) Football League. The USAFE Championship wound down in 1993 due to the end of the Cold War.
Cold War (USAFE and USAREUR)
Cold War (USAFE – Air Force)
Intercontinental Football League College and Air Force Games 1972-1973
United States Air Force in Europe Football League | Finals 1952-1993
United States Air Force in Europe | United Kingdom Sports Conference 1951-1993
United States Air Force in Europe (USAFE) Football League Continental Sports Conference 1956-1960
United States Air Force in Europe (USAFE) Football League France Sports Conference 1953-1955
Cold War (USAREUR – Army)
Northern Italian Football League 1976-1986
United States Armed Forces in Europe | Northern Italian League 1974-1975
United States Army in Europe (USAREUR) Football League Com Z Conference 1953-1960

Picture Credit: [14] Belfast Blitzers | Facebook (2019) Photo 22 August 2019 [Internet] Available from: https://www.facebook.com/belfastblitzers/photos/pcb.2260513057393170/2260507127393763/?type=3&theater [Accessed 23 August 2019]
The American Expeditionary Force (France WWI) and European Theater of Operations (Britain and Northern Ireland WWII) United States Army and Navy Units played Football Leagues during World War I and II in France, Britain, Northern Ireland, and North Africa.
World War I & II (AEF and ETO)
AEFFL (1914-1919); ETO (1940-1945)
World War II (UK & North Africa – Army & Air Force)
European Theater of Operations Championship 1942-1944
ETO Football Championship (Seasons):
Autumn 1944 Spring 1944 Winter 1944 Autumn 1943 Spring 1943
World War I (France – Navy & Army)

[10] Belfast Blitzers | Facebook (2019) Post 21 August 2019: “As promised, a never before seen photo of the game held at Ravenhill in 1942. “ [Internet] Available from: https://www.facebook.com/belfastblitzers/photos/pcb.2258995414211601/2258986244212518/?type=3&theater [Accessed 23 August 2019]
ETO Teams in Ireland (1942-1944)
ETO, USAFE, All-American Festival.
Overview & [Season Roster & Match Reports]:
European Theater of Operations Football Teams
Navy Galloping Gaels went 0-0-1 in the ETO Northern Ireland Championship in Winter 1944
Army Wolverines went 0-0-1 in the ETO Northern Ireland Championship in Winter 1944
Tech Fighting Irish went 0-1 in the ETO Football Championship in Northern Ireland in Autumn 1942
Yarvard went 1-1 in the ETO Football Championship in Northern Ireland in 1942
Hale went 1-0 in the ETO Football Championship in Northern Ireland in 1942

Picture Credit: [10] Belfast Blitzers | Facebook (2019) Post 21 August 2019: “As promised, a never before seen photo of the game held at Ravenhill in 1942. “ [Internet] Available from: https://www.facebook.com/belfastblitzers/photos/pcb.2258995414211601/2258986244212518/?type=3&theater [Accessed 23 August 2019]
US Armed Forces Teams with Irish Connections
WW2
Teams with Irish Nicknames
World War II