In addition, almost 200 West Point graduates who had previously left the Army, including Ulysses S. Approximately 20% of these officers-most of them Southerners-resigned, choosing to tie their lives and fortunes to the Army of the Confederacy. Army, including 1,108 commissioned officers. There were only 16,367 servicemen in the U.S.

Of the 197 companies in the army, 179 occupied 79 isolated posts in the West, and the remaining 18 manned garrisons east of the Mississippi River, mostly along the Canada–United States border and on the Atlantic coast.

Army consisted of ten regiments of infantry, four of artillery, two of cavalry, two of dragoons, and three of mounted infantry. When the American Civil War began in April 1861, the U.S. Recruiting poster for the 1st Battalion New York Mounted Rifles Formation The initial call-up was for just three months, after which many of these men chose to reenlist for an additional three years. Of these soldiers, 596,670 were killed, wounded or went missing. Over the course of the war, 2,128,948 men enlisted in the Union Army, including 178,895 colored troops 25% of the white men who served were immigrants, and further 25% were first-generation Americans. To this end, the Union Army fought and ultimately triumphed over the efforts of the Confederate States Army.

The Union Army was made up of the permanent regular army of the United States, but further fortified, augmented, and strengthened by the many temporary units of dedicated volunteers, as well as including those who were drafted in to service as conscripts. It proved essential to the restoration and preservation of the United States as a working, viable republic. During the American Civil War, the United States Army, the land force that fought to preserve the collective Union of the states, was often referred to as the Union Army, the Federal Army or the Northern Army.

Northern navy civil war