Editing Union army (section)

==Formation==
[[File:Union Private infantry uniform.png|thumb|An illustration of a Union army private infantry uniform]]
[[File:Recruiting poster New York Mounted Rifles.jpg|thumb|Recruiting poster for the [[1st New York Mounted Rifles Regiment]]]]
When the [[American Civil War]] began in April 1861, the U.S. Army included ten regiments of [[infantry]], four of [[artillery]], two of [[cavalry]], two of [[dragoons]], and one of [[mounted rifles]]. The regiments were scattered widely. Of the 197 companies in the U.S. Army, 179 occupied 79 isolated posts in the [[Western United States|West]], and the remaining 18 manned garrisons east of the [[Mississippi River]], mostly along the [[Canada–United States border]] and on the [[East Coast of the United States|U.S. East Coast]]. There were only 16,367 servicemen in the U.S. Army, including 1,108 commissioned officers. Approximately 20% of these officers, most of them [[Southern United States|Southerners]], resigned, choosing to tie their lives and fortunes to the [[Confederate States Army|Confederate army]].<ref>{{Cite book |first=Clayton R. |last=Newell |url=https://history.army.mil/html/books/075/75-1/CMH_Pub_75-1.pdf |archive-url=https://web.archive.org/web/20141023015919/http://www.history.army.mil/html/books/075/75-1/CMH_Pub_75-1.pdf |url-status=dead |archive-date=October 23, 2014 |series=US Army Campaigns of the Civil War|title=The Regular Army before the Civil War, 1845–1860 |pages=50, 52 |publisher=US Army Center of Military History |access-date=26 May 2022}}</ref>

Almost 200 [[United States Military Academy]] graduates who previously left the U.S. Army, including [[Ulysses S. Grant]], [[William Tecumseh Sherman]], and [[Braxton Bragg]], returned to service at the outbreak of the Civil War. This group's loyalties were far more evenly divided. Clayton R. Newell (2014) states, 92 wore Confederate gray and 102 put on the blue of the United States Army.<ref>Newell, p. 52.</ref> Hattaway and Jones (1983), John and David Eicher (2001), and Jennifer M. Murray (2012), state that 99 joined the Confederate army and 114 returned to the Union forces.<ref name=Hattaway9>Hattaway & Jones, pp. 9–10</ref><ref>Eicher, p. 46.</ref><ref>{{Cite book |first=Jennifer M. |last=Murray |url=https://history.army.mil/html/books/075/75-2/CMH_Pub_75-2.pdf |archive-url=https://web.archive.org/web/20121224075449/http://www.history.army.mil/html/books/075/75-2/CMH_Pub_75-2.pdf |url-status=dead |archive-date=December 24, 2012 |series=US Army Campaigns of the Civil War|title=The Civil War Begins, Opening Clashes 1861 |date=2012 |page=9 |publisher=US Army Center of Military History|access-date=26 May 2022}}</ref>

With the [[Confederate States of America|Southern slave states]] declaring secession from the United States, and with a shortage of soldiers in the army, President [[Abraham Lincoln]] [[President Lincoln's 75,000 volunteers|called on the states to raise a force of 75,000 troops]] for three months to put down the Confederate insurrection and defend the national capital in [[Washington, D.C.]] 

Lincoln's call forced the border states to choose sides, and four seceded, making the Confederacy eleven states strong. It turned out that the war itself proved to be much longer and far more extensive in scope and scale than anyone on either side, Union North or Confederate South, expected or even imagined at the outset on the date of July 22, 1861. That was the day that [[United States Congress|Congress]] initially approved and authorized subsidy to allow and support a volunteer army of up to 500,000 troops to the cause.

The call for volunteers initially was easily met by patriotic Northerners, [[Abolitionism in the United States|abolitionists]], and even immigrants who enlisted for a steady income and meals. Over 10,000 [[German Americans]] in [[New York (state)|New York]] and [[Pennsylvania]] immediately responded to Lincoln's call, along with Northern [[French Americans]], who were also quick to volunteer. As more men were needed, however, the number of volunteers fell and both money bounties and forced conscription had to be turned to. Many [[Southern Unionist]]s would also fight for the Union army. An estimated 100,000 white soldiers from states within the Confederacy served in Union army units.<ref>Crofts, Daniel W. [https://digitalcommons.lsu.edu/cgi/viewcontent.cgi?article=3018&context=cwbr CIVIL WAR SESQUICENTENNIAL: Unionism]. ''digitalcommons.lsu.edu''. Retrieved January 29, 2021</ref> Between April 1861 and April 1865, at least 2,128,948 men served in the United States Army, of whom the majority were volunteers.

It is a misconception that the South held an advantage because of the large percentage of professional officers who resigned to join the Confederate army. At the start of the war, there were 824 graduates of the [[United States Military Academy|U.S. Military Academy]] on the active list; of these, 296 resigned or were dismissed, and 184 of those became Confederate officers. Of the approximately 900 West Point graduates who were then civilians, 400 returned to the U.S. Army and 99 to the Confederacy. The ratio of U.S. Army to Confederate professional officers was 642 to 283.<ref name=Hattaway9 /> One of the resigning officers was [[Robert E. Lee]], who had been offered the assignment as commander of a field army to suppress the rebellion. Lee initially disapproved of secession, but refused to bear arms against his native state, [[Virginia in the American Civil War|Virginia]], and resigned to accept the position as commander of the Virginian Confederate forces. Lee eventually became the overall commander of the Confederate army. 

The Confederacy had the advantage of having several military colleges, including [[The Citadel (military college)|The Citadel]] and [[Virginia Military Institute]], but they produced fewer officers. Though officers were able to resign, enlisted soldiers did not have this right. As they usually had to either desert or wait until their enlistment term was over in order to join the Confederate States Army; though few are believed to have done so, their total number is unknown.