The 1st Ohio Infantry Regiment was an infantry regiment in the Union Army during the American Civil War. It served in the Western Theater in a number of campaigns and battles. Three-months regiment With the outbreak of the Civil War in the spring of 1861, President Abraham Lincoln called for 75,000 volunteers from nearly every state. In April, recruiters quickly filled the quota for a number of regiments in the state of Ohio, with several regiments enlisting for 3-months, including a command designated as the 1st Ohio. Mustering in April 17, 1861, under Colonel Alexander M. McCook, the 1st Ohio Infantry Regiment travelled by train to Washington, D.C. for garrison duty in the capital's fortifications and defenses until July. The regiment was placed in Schenck's Brigade, Tyler's Division, Irvin McDowell's Army of Northeastern Virginia. It first saw action at Vienna, Virginia, on June 17 and again on July 9 before occupying Fairfax Court House. It fought at the First Battle of Bull Run and helped cover the army's bitter retreat to Washington. The regiment soon returned to Ohio and mustered out August 2. The regiment was divided into ten separate companies A-K. Each company was stationed out of a different village A-Lancaster B Lafayette C Dayton D Montogomery E Cleveland F Hiberian G Portsmouth H Zanesville I Mansfield K Jaskson. Three-years regiment After the term of service was over in August, a number of the men re-enlisted for 3-years in the reconstituted 1st Ohio Infantry Regiment, under the command of Col. Benjamin F. Smith. The regiment was organized at Camp Corwin in Dayton between August 5 and October 30, receiving muskets, uniforms, and accoutrements. On the last day of August, the regiment entrained for Cincinnati for additional training and guard duty. The regiment left Ohio in November 1861 for Louisville, Kentucky. From there, they were posted in a number of Kentucky towns through February 1862, striving to keep the border state in the Union. In late winter 1862 the regiment was attached to the 4th Brigade, 2nd Division, Army of the Ohio, serving in Tennessee under Don Carlos Buell at Shiloh. There, on April 7, the regiment became engaged at about 10 a.m., losing 2 men killed, 2 officers and 45 men wounded, and 1 man missing. Following Shiloh, the regiment served in Mississippi during the Siege of Corinth before moving to Tuscumbi, Florence, and Huntsville Alabama, June 10 -