It went by the Federal Army, Northern Army, U.S. Army, and the National Army, but the first two are most correct.
If by union you mean the country in post civil war times, The confederate states of America
The Union army (or armies)
Confederate army was the name. They were also called Rebels too.
There were at times several Union armies operating in the Eastern Theater of the US Civil War. The main one was the Army of the Potomac. Other Union armies in the east were the Army of the James, and the Army of Virginia.
The Union Army. wasn't it the Union Arny?
Army of the Potomac
The Union army (or armies)
the Union
Confederate army was the name. They were also called Rebels too.
ARMY OF THE POTOMAC was the major Union Army in the eastern theater of the American Civil War
Yankees
There were at times several Union armies operating in the Eastern Theater of the US Civil War. The main one was the Army of the Potomac. Other Union armies in the east were the Army of the James, and the Army of Virginia.
Other names for the Union were the Republic or simply the United States.
The Union Army. wasn't it the Union Arny?
Army of the Potomac
Army of the Potomac
Within the large parameters of the Confederate military, there were any number of names given to large armies in the US Civil War. For example, two large Southern armies were the Army of Northern Virginia and the Army of Tennessee.
The United States of America instead of the Confederate States or the North.