This is part of the front page of the Philadelphia Inquirer with a map of the First Day of battle. It's my version of "How many things are wrong with this picture?"
The only Petersburg in the area that I know of is modern York Springs. In the 1860s, I've seen it on maps labelled as "Petersburg". If that's the case, that one is way off (it should be at the top edge of the map due north of Hanover.