Three horse-drawn covered wagons in the foreground. Soldiers marching in formation between rows of small cabins and tents in the background.
Source: Stereograph from collection of William A. Pinkerton.
Copyright 1863 by Alexander Gardner.
Library of Congress image.
Closer inspection with cropped images show that the formations are facing towards the camera with a band or drum corps at the front.
The time of year is winter, as evidenced by the winter quarters shown in the image and the bare trees in the background.