Artist John Bachelder drew this map of the Gettysburg battlefield in 1863. In the years following, Bachelder became an expert on the Battle of Gettysburg, studying terrain, interviewing commanders, and walking the battlefield with veterans. He also contributed much effort to memorializing the battle and preserving the battlefield. 

The map is incredibly detailed, showing not only topography and vegetation, but also roads, houses with names of residents, locations of Union and Confederate regiments, and places where officers were killed or wounded.