The primary objective of the Union Army during the Civil War was to preserve the Union and defeat the Confederacy.

Initially, the focus was on preventing the Southern states from seceding and maintaining national unity. As the war progressed, the goal evolved to include the abolition of slavery, particularly after the Emancipation Proclamation in 1863, which aimed to weaken the Confederate war effort. The Union sought to reclaim lost territories, protect key cities, and ultimately restore the United States as a unified nation, highlighting the war's deep political and social implications.