I Corps, 1st Corps, or First Corps may refer to:

• 1st Army Corps (France)
• I Cavalry Corps (Grande Armée), a cavalry unit of the Imperial French Army during the Napoleonic Wars
• I Corps (Grande Armée), a unit of the Imperial French Army during the Napoleonic Wars

• I Cavalry Corps (German Empire), a unit of the Imperial German Army
• I Corps (German Empire), a unit of the Imperial German Army
• I Reserve Corps (German Empire), a unit of the Imperial German Army
• I Royal Bavarian Corps, a unit of the Bavarian Army and the Imperial German Army
• I Royal Bavarian Reserve Corps, a unit of the Bavarian Army and the Imperial German Army
• I Army Corps (Wehrmacht), a unit in World War II
• I SS Panzer Corps, a unit in World War II

• I Corps (British India)
• I Corps (India)

• 1st Army Corps (Russian Empire)
• 1st Guards Assault Aviation Corps
• 1st Guards Mechanized Corps (Soviet Union)
• 1st Airborne Corps (Soviet Union)
• 1st Army Corps (Armed Forces of South Russia), a unit in the Russian Civil War
• 1st Army Corps (Soviet Union)
• 1st Assault Aviation Corps
• 1st Cavalry Corps (Russian Empire)
• 1st Rifle Corps, Soviet Union

• I Corps (United Kingdom)
• I Airborne Corps (United Kingdom)
• 1st Suffolk Artillery Volunteer Corps

• I Corps (United States)
• I Amphibious Corps
• I Armored Corps (United States)
• I Corps (Union Army)
• First Corps, Army of Northern Virginia
• First Corps, Army of Tennessee
• First Army Corps (Spanish-American War)
• I Field Force, Vietnam

• I ANZAC Corps, Australia and New Zealand
• I Corps (Australia)
• I Corps (Belgium)
• I Corps (Bosnia and Herzegovina)
• I Canadian Corps
• I Corps (Czechoslovakia)
• Finnish I Corps (Winter War)
• I Army Corps (Greece)
• I Corps (North Korea)
• I Corps (Ottoman Empire)
• I Corps (Pakistan)
• I Corps (Sri Lanka)
• Polish I Corps (disambiguation), several units
• 1st Territorial Army Corps (Romania)
• I Corps (South Korea)
• I Corps (South Vietnam)
• 1st Corps (Syria)
• 1st Corps (Vietnam People's Army)
• 1st Corps (Yugoslav Partisans), during World War II

• List of military corps by number
• 1st Army Corps (disambiguation)
• 1st Army (disambiguation)
• 1st Brigade (disambiguation)
• 1st Division (disambiguation)
• 1st Regiment (disambiguation)
• 1 Squadron (disambiguation)

This disambiguation page lists articles about military units and formations which are associated with the same title.
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