42nd Regiment

42nd Regiment, 42nd Infantry Regiment or 42nd Armoured Regiment may refer to:

United Kingdom

 * 42nd Regiment of Foot, a unit of the British Army up to 1881, known as the "Black Watch"
 * 42 Engineer Regiment (Geographic), a unit of the British Army Royal Engineers
 * 42nd Royal Tank Regiment, a World War II armoured unit of the British Army
 * 42nd Deoli Regiment, an infantry regiment of the British Indian Army

United States

 * 42nd Infantry Regiment (United States), a unit of the US Army

Union (northern) Army

 * 42nd Illinois Volunteer Infantry Regiment
 * 42nd Indiana Infantry Regiment
 * 42nd Kentucky Infantry Regiment
 * 42nd New York Volunteer Infantry Regiment
 * 42nd Ohio Infantry Regiment
 * 42nd United States Colored Infantry Regiment
 * 42nd Wisconsin Volunteer Infantry Regiment

Confederate (southern) Army

 * 42nd Arkansas Cavalry Regiment
 * 42nd Mississippi Infantry Regiment
 * 42nd Virginia Infantry Regiment

Other nations

 * 42nd Infantry Regiment (Poland), a unit of the Polish Armed Forces of the Second Polish Republic
 * 42nd Armoured Regiment (India), a unit of the Union of the Indian Army
 * 42nd Bomber Aviation Regiment, an aviation unit of the Yugoslav Air Force
 * 42nd Field Artillery Regiment (Lanark and Renfrew Scottish), RCA, a unit of the Canadian Army
 * 42nd Infantry Regiment (France), a former unit in the French Army