A Mail Wagon For the Headquarters of the Army of the Potomac Near Falmouth, Virginia (1863)

A mail wagon for the headquarters of the Army of the Potomac near Falmouth, Virginia, 1863. Animated stereoscopic photographs.

Source.

A Group of Union Telegraph Operators Drinking in Their Quarters Situated Near the Headquarters of the Army of the Potomac During the Siege of Petersburg

A group of Union telegraph operators drinking in their quarters situated near the headquarters of the Army of the Potomac during the Siege of Petersburg near Petersburg, Virginia. By Timothy O’Sullivan. Animated stereoscopic photographs.

Source.

Two Views of Union Soldiers Posing With an Office Wagon Used by the Headquarters of the Army of the Cumberland During the Civil War

Two views of Union soldiers posing with an office wagon used by the headquarters of the Army of the Cumberland at Chattanooga, Tennessee, during the Civil War.

Source 1.
Source 2.

Union Soldiers Posing at General Adelbert Ames Headquarters During the Civil War

View of Union soldiers posing at General Adelbert Ames headquarters during the Civil War.

Source.

Union General John Porter Hatch Posing With His Staff at Headquarters in the South Battery Area of Charleston, South Carolina (1865)

Union General John Porter Hatch posing with his staff at headquarters in the South Battery area of Charleston, South Carolina, 1865. Animated stereoscopic photographs.

Source.

Union Generals George Meade, John Sedgwick, and Robert O. Tyler Posing With Staff Officers at a Headquarters in Brandy Station, Virginia (1864)

Union generals George Meade, John Sedgwick, and Robert O. Tyler posing with staff officers at a headquarters in Brandy Station, Virginia, February 1864. Animated stereoscopic photographs.

Source.

Animate Stereoscopic Portrait of General Grant at His Headquarters at Cold Harbor, Virginia (1864)

Animated stereoscopic portrait of General Ulysses S. Grant at his headquarters in Cold Harbor, Virginia, July 1864. Photographer Mathew Brady is adjusting a reflector on the left. Attributed to Mathew Brady. Published by E. & H. T. Anthony & Company. Animated stereoview.

Source.
Negative version.

Headquarters of the American 3rd Infantry Division Near the Front (1918)

Headquarters of the American 3rd Infantry Division near the front, 1918. Animated stereoview.

Source.

A Band Playing Music For Union Officers at General Alfred Pleasonton Headquarters in Auburn, Virginia (1863)

A band playing music for Union officers at General Alfred Pleasonton's headquarters in Auburn, Virginia, October 1863. By Timothy O'Sullivan. Animated stereoscopic photographs.

Source.

General Orlando Wilcox Posing With His Staff in Camp During the Siege of Petersburg (1864)

Union General Orlando Wilcox of the 3rd Division, IX Corps, posing with his staff in camp during the Siege of Petersburg, 1864. Animated stereoscopic photographs.

Source.

Three Views of a Union Convalescent Camp During the Civil War Near Alexandria, Virginia

Animated stereoscopic photographs.

Three views of Union soldiers and other unidentified men in a convalescent camp near Alexandria, Virginia. Possibly all taken by Andrew J. Russell as other views taken near where these were taken in the camp were also taken by him. All of them seem to be attributed to Mathew Brady by NARA however.

Source 1.
Source 2.
Source 3.

General Ambrose Burnside, Mathew Brady, and Other Union Officers in Cold Harbor, Virginia (1864)

General Ambrose Burnside (right) reading a newspaper as photographer Mathew Brady (center left) and other Union officers are seen posing next to him at a headquarters in Cold Harbor, Virginia, 1864. Animated stereoscopic photographs.

Source.

Union Soldiers of the 93rd New York Volunteer Infantry Regiment in Bealeton, Virginia (1863)

Union soldiers of the 93rd New York Volunteer Infantry Regiment in camp in Bealeton, Virginia, 1863. By Timothy O'Sullivan. Animated stereoscopic photographs.

Source.

Time-lapsed Photographs of a Cock Fight at Union General Orlando B. Willcox's Headquarters Near Petersburg, Virginia

Time-lapse photographs of a cock fight at Union General Orlando B. Willcox's headquarters near Petersburg, Virginia, c. 1865.

Source 1.
Source 2.

Union Officers Posing as if in the Middle of a Mock Brawl

"A muss at headquarters," Union officers posing as if in the middle of a mock brawl, Falmouth, Virginia, 1863. By James Gibson. Animated stereoscopic photographs taken within a fraction of a second of each other.

Source.