First Bull Run

The First Battle of Bull Run was the 12th battle of the Civil War. It took place in Virginia, on July 21st, 1861, and ended in a solid victory for the Confederate states. The victory was led by Joseph E. Johnston and P.G.T. Beauregard. The loss for the Union was led by Irvin McDowell, and the Union suffered a little less than 3,000 casualties with 460 men dead. The Confederacy suffered a great deal less in their amount of overall casualties, but with only 387 men killed. The Confederacy pulled a good one over on the Union due to capturing over a thousand of their soldiers.

Fort Henry and Donelson

This victory for the Union was led by Ulysses S. Grant in a combined attack by land and water upon both Fort Henry and Fort Donelson in Tennessee on February 6th, and February 12th through February 16th in 1862.
"These victories were the first good news for the North and signaled the presence of Ulysses S. Grant." - Thomas Flagel
There were only 40 casualties for the Union and 79 for the Confederacy during the quick battle at Fort Henry.
However, the surrender at Fort Donelson left the Union with nearly 2,700 casualties, and 13, 846 for the Confederacy.

Capture of New Orleans

This battle was a win for the Union due to driving the Confederate troops out of Louisiana (where the battle took place) and into the bloodbath of Shiloh on April 23rd-25th, 1862. This loss was a crushing blow to the South. The North captured a metropolis of 180,000, gained inroads to the Confederate interior, seized the lower portion of Mississippi, and added a premium port to its blockade operations. Getting all of that merely costed them 36 men killed and 135 wounded.

Gettysburg

The battle of Gettysburg in Pennsylvania on July 1st-3rd in 1863  was the largest and bloodiest battle ever fought in the Western Hemisphere. It provided a major surge in Union morale. Confederate General Robert E. Lee  loses to Union Major General George Gordon Meade, resulting in a Union victory, but at the great cost of many men lost. 3, 155 of the Union's men killed, and 4,708 Confederate soldiers dead.  Pickett's Charge fails, which ends the second invasion of the North.

The Surrender of Vicksburg

The end to the four year-long war took place in Mississippi on July 4, 1863, but was merely the result of a long battle that began on the 18th of May in the same year; an entire month prior. This final battle, a victory and resolved win for the Union, led by  Major General Ulysses S. Grant against Lieutenant General John C. Pemberton, had cost the Union 4,835 casualties and 3,202 for the defeated Confederacy. With no re-enforcement, supplies nearly gone, and after holding out for more than forty days, the Confederate soldiers  finally surrendered on July 4. This action yielded command of the Mississippi River to the Union forces, who would hold it for the rest of the conflict.