75th Ohio Infantry The 75th Ohio Volunteer Infantry was an infantry regiment from southwestern Ohio in the Union Army during the American Civil War . It served in the Eastern Theater , most notably in the battles of Chancellorsville and Gettysburg and then in the siege operations against Charleston , South Carolina . Service history . 1862 . The infantry regiment was organized at Camp John McLean near Cincinnati , Ohio , from November 7 , 1861 , to January 8 , 1862 , to serve three years . The 75th Ohio was initially led by Col . Nathaniel C . McLean , Lt . Col . R . A . Constable and Maj . Robert Reily . The regiment began its service with 984 officers and men . Among the enlistees was future U . S . Congressman Henry Lee Morey . The 75th was initially sent to augment the Union forces in the Shenandoah Valley region of Virginia . It soon participated in defending what became known as Stonewall Jackson ' s Valley Campaign . On May 8 , 1862 , at the Battle of McDowell , the regiment lost 87 men . It fought again at Cross Keys before being sent eastward to reinforce the Union troops after the Peninsula Campaign . The 75th OVI then participated in the subsequent Northern Virginia Campaign and fought in the Second Battle of Bull Run , where it lost 113 men . Within a month , it saw action at the Battle of South Mountain in Central Maryland . 1863 - Chancellorsville . During the Battle of Chancellorsville in May , the 75th Ohio was part of the 2nd Brigade , 1st Division of the XI Corps in the Army of the Potomac . During the battle , the XI Corps was far from the Confederate army , so their commander , Maj . Gen . Oliver O . Howard did not have them dig defenses in case of an attack despite being ordered to do so by Maj . Gen . Joseph Hooker . On May 2 , Confederate General Robert E . Lee decided on a daring and very risky plan . Knowing the XI Corps was not prepared for an attack , he sent General Thomas " Stonewall " Jackson and his Second Corps of 28 , 000 men on a 12 - mile march around the Union right flank with the hope of catching the XI Corps by surprise . At 4 : 30 in the afternoon , the 75th ' s commander , Col . Robert Reily , had heard reports of a Confederate movement in his direction . Unlike many other commanders , including General Howard , Reily did not dismiss them . He prepared the 75th Ohio for an attack he knew was coming . He had his men lie down and rest by their guns and wait for the attack . Within a half hour , Jackson ' s Corps rushed out of the thick underbrush . When Jackson ' s corps struck at about 5 p . m . , the XI Corps was completely unprepared , many of the men engaged in eating supper . Most of the XI Corps was taken by surprise and broke for the rear without firing a shot . As other men of the XI Corps ran by in a panic , the 75th Ohio stood and fired back at the Confederates . They kept up the fire for ten minutes until the Confederates had overwhelmed their lines forcing them to retreat . In those ten minutes , Colonel Reily was killed , while 150 other men of the 75th Ohio were killed or wounded . 1863 - Gettysburg . At the Battle of Gettysburg on July 1 – 3 , 1863 , the 75th Ohio , now under the command of Colonel Andrew L . Harris ( future 44th Governor of Ohio ) , arrived with the rest of the XI Corps on the battlefield mid - day on July 1 , 1863 , the first day of the battle . The fighting had been going on since morning . As part of Brig . Gen . Francis C . Barlow ' s division , the 75th Ohio took a defensive position on Blocher ' s Knoll ( now known as Barlow ' s Knoll ) , north of the town . Unfortunately , this slight rise in the terrain was too far forward in comparison to the other XI Corps divisions , and Barlow ' s position formed a salient that could be attacked from multiple sides . Confederate Lt . Gen . Richard S . Ewell sent two brigades , those of Brig . Gen . George P . Doles and Brig . Gen . John B . Gordon , in a frontal assault on the knoll . Barlow ' s division was overwhelmed , suffering serious losses , and Barlow was wounded and left on the field for dead . Harris led his men in a successful withdrawal through the hotly contested streets to Cemetery Hill , where they entrenched on the northeastern slope . Harris took command of the 2nd Brigade after its commander , Brig . Gen . Adelbert Ames , took Barlow ' s place as commander of the 1st Division . At around 7 : 30 at night on July 2 , the 75th Ohio , positioned between the 25th Ohio Infantry and the 17th Connecticut Infantry regiments , now on a brickyard lane at the base of East Cemetery Hill , held off attacks by regiments of Brig . Gen . Harry T . Hays ' " Louisiana Tigers " brigade . Overall , the Buckeyes lost 186 officers and men ( 16 killed , 74 wounded and 96 missing ) at Gettysburg . Actions later in the war . In August , the 75th OVI was transferred to Charleston Harbor , remaining in the trenches in South Carolina until September . The 75th then moved to Folly Island , and then to Florida , where the men were mounted and designated as mounted infantry . The regiment served in Florida until the close of the war , participating in the Battle of Gainesville on August 17 . Six companies were mustered out in October and November 1864 , while the veterans remained in the service until August 1865 . Monuments . There are two combined monuments to the 25th and the 75th Ohio Regiments in the Gettysburg National Military Park . One is north of Gettysburg on East Howard Avenue on Barlow ' s Knoll ( their position on the First Day ) . The second is on Wainwright Avenue ( approximating the former brickyard lane ) on East Cemetery Hill ( their position on the Second Day ) . Further reading . < div class = " references - small " >