Editing Union army (section)

===Inspector General's Department===
{{main|Office of the Inspector General of the United States Army}}
At the start of the Civil War, there was technically no Inspector General's Department, with neither a set of operating practices or centralized direction.  Instead there were two [[Inspector General]]s (IGs) with the rank of colonel whose duty was to conduct inspections and investigations to ensure the army was organized and operating at full readiness, but these were done in an ad-hoc manner at the discretion of the Secretary of War.  As the war progressed and membership in the inspectorate increased, the duties of IGs and assistant IGs were continually redefined, to the extent that any time a problem was identified the common response was simply to assign an inspector to it.  Eventually in January 1863 a permanent office of the IG was established in Washington, and it was from here that the process of exerting a centralized control over IGs in the field and crafting standard policies and procedures was started.<ref name="Newell94">Newell & Shrader, p. 90–94</ref>

In August 1861, Congress authorized an increase of two additional IGs with the rank of colonel and five assistant IGs with the rank of major from among the regular army.  This number stayed the same throughout the entire war, with the addition of a small civilian clerical staff once the Washington office was established.  Congress eventually determined that each geographical department, army, corps, division and brigade would also be assigned an IG or assistant IG, however these positions were to be filled by regular or volunteer officers detailed from line units of the army or from the other staff departments.<ref name="Newell94"/>

The inspectorate faced many challenges during the Civil War, including hostility and lack of cooperation from some commanders and the mixed performance of some IGs in the field.  Despite these issues it was able to successfully meet the challenges of the war overall, particularly with bringing under control the waste, fraud and abuse which had been rampant at the start of the conflict.<ref name="Newell94"/>
;Leadership
At the start of the war the inspectorate consisted of Colonel [[Sylvester Churchill]], the senior IG of the army, and Colonel [[Joseph K. Mansfield]], the junior IG.  Churchill however took leave in April 1861 on account of his health and formally retired in September that year, while Mansfield was promoted to major-general and left to command troops in May.  Colonel [[Henry Lee Scott]] replaced Mansfield that same month, but when Churchill retired his position was given to Colonel [[Randolph Marcy]], father-in-law to George McClellan, in the same month.  Serving as the chief of staff to McClellan, Marcy did not formally take up his duties as senior IG until after the [[Battle of Antietam]], by which point however his association with McClellan had soured Marcy's relationship with Secretary Stanton, who sent him on inspection tours of various geographical departments.  Instead, the [[de facto]] leader of the inspectorate was whoever was the IG in charge of the Washington office, which was Colonel [[Delos Sacket]] between January 1863 and March 1864, and Colonel [[James Allen Hardie]] for the remainder of the war.<ref name="Newell94"/>