When you took a American Civil War, the Union was the title utilized to refer to the United States, the northern states that did non secede. Since the term got been utilized before a war to refer to the entire United States (a "union of states"), applying it to use to a non-secessionist side carried the connotation of legitimacy when the continuation of the pre-existing political unit. Too, in the public dialogue of the United States, newly states come "admitted to the Union" & a President's annual address to Congress and to the people is referred to as the "State of the Union" Address.

In a period of the American Civil War, Loyalists to the United States sleep in the Border States & Confederate States were termed Unionists. About 120,000 Southern Unionists served in a Union Army in the period of the Civil War, & each Southern state, except South Carolina, raised 'Unionists' regiments. Southern Unionists were extensively utilized when anti-guerrilla forces & when occupation troops within areas of the Confederacy occupied per Union.

Since a Civil War, a term has been a widely utilized equivalent word for the Northern side of the conflict, & has progressively misplaced the extra subtle historical connotations. These are normally utilized inside contexts in which "United States" can become confusing, "Federal" obscure, or even "Yankee" dated or even derogative. Case utilizes:

Union General Ulysses S. Grant Union Army of the Potomac Union cavalry

Even so, a term Union remains extra popular by owning historiographer than it does by using a general public.