- The Battle of Gettysburg (July 1-3, 1863): Often referred to as the turning point of the Civil War, the Battle of Gettysburg was a significant Union victory that ended General Robert E. Lee's second invasion of the North. The three-day battle resulted in heavy casualties on both sides, but the Union victory boosted morale and strengthened their position.
- The Battle of Vicksburg (May 18-July 4, 1863): This battle was crucial in gaining control of the Mississippi River and splitting the Confederacy in two. Union forces led by General Ulysses S. Grant besieged the Confederate stronghold of Vicksburg for over six weeks before its surrender. The Union victory cut off supplies and reinforcements to the Confederate western territories and gave the Union control of the river, a major strategic advantage.
- The Battle of Antietam (September 17, 1862): Although it ended in a tactical draw, the Battle of Antietam is considered a significant Union victory as it halted General Lee's first invasion of the North. The battle was the bloodiest single-day battle in American history, with over 22,000 casualties. The Union victory led to President Abraham Lincoln issuing the Emancipation Proclamation, declaring freedom for enslaved people in Confederate territories.