An opening spread from Freeman Colby Vol. 4:

NOTES & PRINTABLES >>
TEXT SOURCE:
Freeman Colby’s letter of 1 June 1864 >>
Colby’s salutation gives us scant details about his location:

VISUAL SOURCES:
Fortunately several “Special Artists” were on hand to sketch the army crossing at Hanover Ferry:

My favorite part of this quick sketch by Forbes is the rushed shortcuts — Instead of drawing a hundred marching men, he just writes “infantry marching over the bridge” across the pontoon span!

^ “Crossing on the Pamunkey–at Hanover Ferry” (Waud / ~27-29 May 1864) [LOC.gov]
Waud takes more time to draw his figures — fleshing out a couple & leaving the rest for his home-office engravers to fill in.
I had to mirror both these images horizontally, so that the action moved from left to right across the comics pages:
ANOTHER VIEW OF THE SCENE:

Amazingly, Timothy O’Sullivan was right up on the hill in Waud’s background, looking down with his camera equipment! (Is that Forbes & Waud sketching in the tent across the river?)
It’s amazing. That these moments were captured. And in the photo there’s a guy on his phone, facing the tree taking a photo of something the other guy found! Grin.
I see it! Gadzooks, proof that the upcoming time-travelling selfie fad has already come & gone!