Photo of Union Soldiers of the 6th Massachusetts Militia Regiment Posing in Battle Monument Square in Baltimore, Maryland (1861)

Portrait photo of Union soldiers of the 6th Massachusetts Militia Regiment posing in front of the War of 1812 Battle Monument in Battle Monument Square in Baltimore, Maryland, July 1, 1861. Attributed to photographer William Weaver. I think it is a possibility that using a studio portrait lens to take this outdoor photograph caused the edges of it to look so out of focus.

Source: Library of Congress.

View of Scaffolding Built For the Construction of Cabin John Bridge in Cabin John, Maryland (1859)

 

View of scaffolding built for the construction of Cabin John Bridge (also known as the Union Arch Bridge) in Cabin John, Maryland, c. 1859. The bridge was built as part of the Washington Aqueduct project. The dam in the foreground is holding up the waters of Cabin John Creek. Attributed to Titian Ramsay Peale.

Source: National Museum of American History.

Photo of a Stretch of the C&O Canal Near Little Falls on the Potomac River (1850s)

 

 

View of a stretch of the Chesapeake and Ohio Canal near Little Falls on the Potomac River close to the Maryland/Washington, D.C., border line, c. 1855-1860. Attributed to Titian Ramsay Peale.

Source: National Museum of American History.

View of a Parade of Zouaves and Other Soldiers on Broadway in Baltimore, Maryland, Possibly Taken During the Civil War (1860s)

 

 

 

 View of Zouaves and other soldiers during a parade along Broadway in Baltimore, Maryland, c. 1860s. Attributed to photographer William Chase. The wagon seen at right is possibly a military one. Originally published as a stereoview. NYPL dates this photo to 1880, but I think it was taken much earlier.

Source: New York Public Library.

Portrait of President Millard Fillmore Attributed to Baltimore Photographer Jesse Harrison Whitehurst (1850′s)

Portrait of President Millard Fillmore attributed to Baltimore photographer Jesse Harrison Whitehurst, c. 1850′s.

Source: Library of Congress.
More information.

Portrait of Union Surgeons and Other Medical Personnel Serving With the 2nd New Hampshire Volunteer Infantry Regiment Posing in Front of a Tent in an Encampment in Bladensburg, Maryland, During the American Civil War (1861)

Portrait of Union surgeons and other medical personnel serving with the 2nd New Hampshire Volunteer Infantry Regiment posing in front of a tent in an encampment in Bladensburg, Maryland, during the American Civil War, August 1861. From the book A History of the Second Regiment, New Hampshire Volunteer Infantry, in the War of the Rebellion published in 1896.

Portrait of Midshipmen of the United States Naval Academy Class of 1866 Posing in Front of the Herndon Monument in Annapolis, Maryland (1866)

Portrait of midshipmen of the United States Naval Academy Class of 1866 posing in front of the Herndon Monument in Annapolis, Maryland, c. 1866. From Miller's Photographic History of the Civil War.

Daguerreotype Portrait of United States Senator and Governor of Maryland Thomas George Pratt (1850′s)

Daguerreotype portrait of United States Senator and Governor of Maryland Thomas George Pratt, c. 1850′s. By Mathew Brady.

Source.

Animated Stereoscopic Portrait of Maryland Governor and Congressman Francis Thomas (1860's)

Animated stereoscopic portrait of Maryland governor and congressman Francis Thomas, c. 1860's. By Mathew Brady.

Source.

Union Soldiers of the Boston Light Artillery Posing With Their Guns in a Fortified Battery Overlooking the Thomas Viaduct in Elkridge, Maryland (1861)

Union soldiers of the Boston Light Artillery posing with their guns in a fortified battery overlooking the Thomas Viaduct in Elkridge, Maryland, 1861. The Baltimore and Ohio Railroad ran across the viaduct which was part of the only railroad connection into Washington, D.C., during the Civil War.

Source.
More information.

A Group of Union Officers, Scouts, and Agents Posing in Front of a Tent on the Antietam Battlefield Near Sharpsburg, Maryland (1862)

A group of Union officers, scouts, and agents including head of Union intelligence operations, Allan Pinkerton, posing in front of a tent on the Antietam battlefield near Sharpsburg, Maryland, October 1862.

Source.

Tintype Portrait of Union Soldier Corporal Sidney S. Goodridge Posing in Front of a Hut at Camp Benton Near Edwards Ferry, Maryland, During the Civil War

Tintype portrait of Union soldier Corporal Sidney S. Goodridge posing in front of a hut at Camp Benton near Edwards Ferry, Maryland, during the Civil War. He served with Company K of the 20th Massachusetts Volunteer Infantry Regiment and Company B of the 4th Massachusetts Heavy Artillery Regiment.

Source.

View of Union Soldiers Guarding a Pontoon Bridge Crossing the Potomac River Connecting Virginia With Brunswick, Maryland (1862)

View of Union soldiers guarding a pontoon bridge crossing the Potomac River connecting Virginia, in the foreground, with Berlin (now Brunswick), Maryland, October 1862. The bridge on the right was destroyed by Confederate forces. By Alexander Gardner. Animated stereoscopic photographs.

Source.

Union Soldiers of the Independent Battery B, Pennsylvania Light Artillery Posing With Their Guns on the Antietam Battlefield Shortly After the Battle There Near Sharpsburg, Maryland (1862)

Union soldiers of the Independent Battery B, Pennsylvania Light Artillery posing with their guns on the Antietam battlefield shortly after the battle there near Sharpsburg Maryland, September 20, 1862. By Alexander Gardner. Animated stereoscopic photographs.

Source.

Union Soldiers of the 22nd Regiment New York State Militia Drilling in Square Formation Near Harpers Ferry on Maryland Heights, Maryland (1862)

Union soldiers of the 22nd Regiment New York State Militia drilling in square formation near Harpers Ferry, on Maryland Heights, Maryland, c. 1862.

Source 1.
Source 2.

A Group of Union Artillery Officers Posing in Front of a Tent on the Antietam Battlefield (1862)

A group of unidentified Union artillery officers posing in front of a tent on the Antietam battlefield shortly after the battle there near Sharpsburg, Maryland, September 1862. By Alexander Gardner. Animated stereoscopic photographs.

Source.

Union Officers Colonel John S. Crocker, Lieutenant Colonel Benjamin C. Butler, and Another Unidentified Man of the 93rd New York Volunteer Infantry Regiment Posing in Front of a Tent on the Antietam Battlefield (1862)

Union officers Colonel John S. Crocker, Lieutenant Colonel Benjamin C. Butler, and another unidentified man of the 93rd New York Volunteer Infantry Regiment posing in front of a tent on the Antietam battlefield shortly after the battle there, September 1862. By Alexander Gardner. Animated stereoscopic photographs.

Source.

Portrait of Allan Pinkerton and Four Other Unidentified Men Posing in Front of a Tent on the Antietam Battlefield (1862)

Portrait of Union intelligence chief Allan Pinkerton (sitting on left) and four other unidentified men posing in front of a tent on the Antietam battlefield shortly after the battle there near Sharpsburg, Maryland, September 1862. By Alexander Gardner. Animated stereoscopic photographs.

Source.

Union General John C. Caldwell and his Staff Posing on the Antietam Battlefield (1862)

Union General John C. Caldwell and his staff posing in front of a tent on the Antietam battlefield shortly after the battle there, September 1862. By Alexander Gardner. Animated stereoscopic photographs.

Source.

Dead Confederate Soldiers in the Bloody Lane With Union Soldiers Posing Behind Them After the Battle of Antietam (1862)

Dead Confederate soldiers in the Bloody Lane with Union soldiers, probably part of a burial detail, posing behind them after the Battle of Antietam, 1862. By Alexander Gardner. Animated stereoscopic photographs.

Source.