The 23rd Ohio Infantry Regiment was an Ohian regiment of the Union Army that was active from 1861 to 1865 during the American Civil War. The regiment was organized in Columbus, and future Presidents Rutherford B. Hayes and William McKinley served in the unit. The 23rd Ohio was garrisoned in West Virginia, and it first fought at the Battle of Carnifex Ferry before taking part in the Maryland campaign, fighting off Morgan's Raid, the Lynchburg campaign, and the Valley Campaigns of 1864.