The Chubachus Library of Photographic History

A group of Union officers, scouts, and agents including head of Union intelligence operations, Allan Pinkerton, posing in front of a tent...

Portrait of Union intelligence chief Allan Pinkerton (sitting on left) and four other unidentified men posing in front of a tent on the A...

  A group of Union intelligence agents posing in front of Great Falls on the Virginia side of the Potomac River. Animated stereoview. ...