The Union Army of the Potomac fought in most of the Eastern Theater campaigns, primarily in (Eastern) Virginia, Maryland, and Pennsylvania. After the end of the war, it was disbanded on June 28, 1865, shortly following its participation in the Grand Review of the Armies.
Because of its proximity to the large cities of the North, such as Washington, D.C., Philadelphia, and New York City, the Army of the Potomac received more contemporary media coverage than the other Union field armies. Such coverage produced fame for a number of this army's units. Individual brigades, such as the Irish Brigade, the Philadelphia Brigade, the First New Jersey Brigade, the Vermont Brigade, and the Iron Brigade, all became well known to the general public, both during the Civil War and afterward.
- Brigadier General Irvin McDowell: Commander of the Army and Department of Northeastern Virginia (May 27 – July 25, 1861)
- Major General George B. McClellan: Commander of the Military Division of the Potomac, and later, the Army and Department of the Potomac (July 26, 1861 – November 9, 1862)
- Major General Ambrose E. Burnside: Commander of the Army of the Potomac (November 9, 1862 – January 26, 1863)
- Major General Joseph Hooker: Commander of the Army and Department of the Potomac (January 26 – June 28, 1863)
- Major General George G. Meade: Commander of the Army of the Potomac (June 28, 1863 – June 28, 1865; Major General John G. Parke took brief temporary command during Meade's absences on four occasions during this period); Lt. Gen. Ulysses S. Grant, general-in-chief of all Union armies, located his headquarters with the Army of the Potomac and provided operational direction to Meade from May 1864 to April 1865, but Meade retained formal command.
Major Battles and Campaigns
- First Bull Run Campaign or First Manassas: McDowell
- Peninsula Campaign, including the Seven Days Battles: McClellan
- Northern Virginia Campaign, including the Second Battle of Bull Run (three corps participated under the control of the Army of Virginia)
- Maryland Campaign, including the Battle of Antietam or Sharpsburg: McClellan
- Fredericksburg Campaign: Burnside
- Chancellorsville Campaign: Hooker
- Gettysburg Campaign: Meade
- Bristoe Campaign: Meade
- Mine Run Campaign: Meade
- Overland Campaign: Meade
- Richmond-Petersburg Campaign, including the Battle of the Crater: Meade
- Appomattox Campaign, including Lee's surrender at Appomattox Court House: Meade