This scene depicts a portrait of Knap's Independent Battery E, of the Union XII Corps. The battery unlimbered in the vicinity of where the Miller cornfield meets the East Woods, and eventually was moved approximately just north of where Mumma's farm lane intersects with the Smoketown road sometime after Sedgwick's repulse from the West Woods. Here it supported the Union's second drive into the West Woods, which was undertaken by Tyndale's Ohio Brigade of the XII Corps (the monument to Tyndale's troops is visible on the right of view 1). A section of the battery was moved to a position just opposite the Dunker Church, when a sudden Confederate thrust drove the Union troops out of the West wood. The location of this photograph approximately matches the most advanced position of the battery.

The photograph was taken sometime before the afternoon of September 19th, when the battery along with the entire XII Corps was ordered to move out to Harper's Ferry.