[Berlin (now Brunswick), Md. Pontoon bridge and ruins of the stone bridge across the Potomac (destroyed in 1861)] (LOC), a photo by The Library of Congress on Flickr.
This October 1862 photo of the Potomack River at what is now called Brunswick, MD is from the amazing Civil War collection at the library of congress.
Here, at the city now known as Brunswick, MD but then called "Barry" and later "Berlin", are a pontoon bridge along with the ruins of a stone bridge across the Potomac. The stone structure was destroyed in 1861.
A. Gardner was the photographer.
Note the telegraph pole to left. The pontoon bridge was built by Union troops across the Potomac River as part of their military operations. This view was taken looking from Virginia towards the town.
The town is about 30 miles south of Antietam, and the photographer was in the area to document the main eastern theater of the war, Battle of Antietam, September-October 1862.