During the American Civil War, a department was a geographical command within the Union's military organization, usually reporting directly to the War Department. Many of the Union's departments were named after rivers or other bodies of water, such as the Department of the Potomac and the Department of the Tennessee. The geographical boundaries of such departments changed frequently, as did their names. As the armies became larger Departments began to be subordinated to Military Divisions, and the Departments were often sub divided into Districts and from 1862 Subdistricts. Much information on Civil War departments can be found in Eicher & Eicher, Civil War High Commands.
The Army of the Ohio was the name of two Union armies in the American Civil War. The first army became the Army of the Cumberland and the second army was created in 1863.
The Department of the Ohio was an administrative military district created by the United States War Department early in the American Civil War to administer the troops in the Northern states near the Ohio River.
The 26th Kentucky Infantry Regiment was an infantry regiment that served in the Union Army during the American Civil War.
The 1st Ohio Cavalry Regiment was a cavalry regiment that served in the Union Army during the American Civil War.
The Department of Virginia and North Carolina was a United States Military department encompassing Union-occupied territory in the Confederate States during the Civil War. In 1863 it was formed by the merging of two previously existing departments: the Department of Virginia and the Department of North Carolina. In 1865 the two departments were once again separated.
The 5th Tennessee Infantry Regiment was an infantry regiment that served in the Union Army during the American Civil War.
The 6th Regiment Tennessee Volunteer Infantry was an infantry regiment that served in the Union Army during the American Civil War.
Battery K, 1st Ohio Light Artillery was an artillery battery that served in the Union Army during the American Civil War.
Battery L, 1st Ohio Light Artillery was an artillery battery that served in the Union Army during the American Civil War.
The 62nd Ohio Infantry Regiment was an infantry regiment in the Union Army during the American Civil War.
The 67th Ohio Infantry Regiment was an infantry regiment in the Union Army during the American Civil War.
The 82nd Ohio Infantry Regiment, sometimes 82nd Ohio Volunteer Infantry was an infantry regiment in the Union Army during the American Civil War.
12th Ohio Battery was an artillery battery that served in the Union Army during the American Civil War.
Battery D, 1st Rhode Island Light Artillery Regiment was an artillery battery that served in the Union Army during the American Civil War.
The 13th Indiana Infantry Regiment, was an infantry regiment in the Union Army during the American Civil War.
1st Connecticut Heavy Artillery Regiment was an artillery regiment that served in the Union Army during the American Civil War.
Battery "G" 4th Regiment of Artillery was a light artillery battery that served in the Union Army during the American Civil War.
The 2nd Maryland Infantry, Potomac Home Brigade was an infantry regiment that served in the Union Army during the American Civil War.
Independent Battery D, Pennsylvania Light Artillery, was an artillery battery that served in the Union Army during the American Civil War. The unit organized on 21 September 1861 and served until 13 June 1865. The battery participated in the battles of Second Bull Run, Chantilly, South Mountain, Antietam, and Fredericksburg in 1862. The following year, Battery D transferred to the Western theater where it took part in the Siege of Vicksburg and other operations. The years 1864–65 saw the unit fight at the first Petersburg assault, the Crater, Ream's Station, Battle of Peebles's Farm, Fort Stedman, and the final Petersburg assault. Battery D took part in the Grand Review of the Armies before being mustered out.
Battery "L", 1st Illinois Light Artillery Regiment was an artillery battery from Illinois that served in the Union Army during the American Civil War. The battery was organized in February 1862 at Chicago and guarded prisoners until June 1862. The battery spent the remainder of the war on guard duty in West Virginia without seeing any major actions. The soldiers were mustered out in July 1865.