4th Corps Observation Group
Officers and men of the 135th Aero Squadron, November 1918, Gengault Aerodrome (Toul), France
Active	1 July 1918-1919
Country	United States
Branch	Air Service, United States Army
Type	Group
Role	Command and Control
Part of	American Expeditionary Forces (AEF)
Engagements	World War I

The 4th Corps Observation Group was a Air Service, United States Army unit that fought on the Western Front during World War I. It was demobilized in April 1919 as part of the Air Service, First United States Army. There is no modern United States Air Force unit that shares its lineage and history.

 This article incorporates public domain material from the Air Force Historical Research Agency

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Category

Category:20th-century military history of the United States Category:Aviation in World War I