Hanovertown Ferry, Virginia. Canvas pontoon bridges at Hanovertown Ferry, constructed by the 50th New York Volunteer Engineers, May 28, 1864 (Timothy O'Sullivan/ Library of Congress)

Hanovertown Ferry, Virginia. Canvas pontoon bridges at Hanovertown Ferry, constructed by the 50th New York Volunteer Engineers, May 28, 1864 (Timothy O’Sullivan/ Library of Congress)