Portrait of Private Ira Fish, 150th New York Infantry, U.S.A.
(Source: Library of Congress)
In the Union army, early in the war, soldiers wore a variety of uniforms. Many groups wore uniforms of their native country. For example, soldiers of Scotish decent often wore kilts. As the war went on, a standard uniform design emerged.
Infantry officers and enlisted men wore dark blue frock coats hanging to mid thigh. High ranking officers including majors, lieutenant colonels, colonels, and generals wore double-breasted coats. Lower ranking soldiers wore single breasted frock coats.