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23rd Marching Regiment of Foreign Volunteers, a unit of the French Army •
23rd Regiment of Bombay Light Infantry, a unit of the British Army •
23rd Regiment of Foot, a unit of the British Army •
23rd Infantry Regiment (United States), a unit of the United States Army •
23rd Marine Regiment (United States), a unit of the United States Marine Corps •
23rd Arkansas Infantry Regiment, a unit of the Confederate States Army •
23rd Tennessee Infantry Regiment, a unit of the Confederate States Army •
23rd Connecticut Infantry Regiment, a unit of the Union Army •
23rd Indiana Infantry Regiment, a unit of the Union Army •
23rd Illinois Infantry Regiment, a unit of the Union Army •
23rd Iowa Volunteer Infantry Regiment, a unit of the Union Army •
23rd Regiment Kentucky Volunteer Infantry, a unit of the Union Army •
23rd Regiment Massachusetts Volunteer Infantry, a unit of the Union Army •
23rd Michigan Infantry Regiment, a unit of the Union Army •
23rd Missouri Infantry Regiment, a unit of the Union Army •
23rd New York Infantry Regiment, a unit of the Union Army •
23rd Ohio Infantry, a unit of the Union Army •
23rd Pennsylvania Infantry, a unit of the Union Army •
23rd Wisconsin Volunteer Infantry Regiment, a unit of the Union Army ==Cavalry regiments==