Abraham Lincoln was the President of the United States, or Union, during the US Civil War.
Grant was a Civil War General and president.
Abraham Lincoln was the President of the Union in the Civil War.
Abraham Lincoln
Lincoln
Abraham Lincoln
The Civil War between the Confederates and the Union.
In their capacity of the Union and CSA commander in chief they led and ruled the North and the South during the Civil War.
If you mean The Union in the US Civil War, President Abraham Lincoln lead the Union. If you mean who led A Union, President Ronald Regan was, at one time a union president.
Ulysses S. Grant
U.S. Grant
President Abraham Lincoln