42nd Regiment

• 42 Engineer Regiment (Geographic)
• 42 Squadron (disambiguation)
• 42nd Arkansas Cavalry Regiment
• 42nd Armoured Regiment (India)
• 42nd Battalion (disambiguation)
• 42nd Bomber Aviation Regiment
• 42nd Brigade (disambiguation)
• 42nd Deoli Regiment
• 42nd Division (disambiguation)
• 42nd Field Artillery Regiment (Lanark and Renfrew Scottish), RCA
• 42nd Group (disambiguation)
• 42nd Illinois Volunteer Infantry Regiment
• 42nd Indiana Infantry Regiment
• 42nd Infantry Regiment (France)
• 42nd Infantry Regiment (United States)
• 42nd Kentucky Infantry Regiment
• 42nd Mississippi Infantry Regiment
• 42nd New York Volunteer Infantry Regiment
• 42nd Ohio Infantry
• 42nd Regiment of Foot
• 42nd Royal Tank Regiment
• 42nd United States Colored Infantry
• 42nd Virginia Infantry
• 42nd Wisconsin Volunteer Infantry Regiment