Yes, a crucial one
The town of Gettysburg and the ground over which it was fought is in Pennsylvania so it is Union. It was a Union victory as well.
Gettysburg
It was a Union victory, sometimes considered to be a "decisive victory" (meaning it had a major impact on how the war ended).
The Battle Of Gettysburg resulted in a Union (US) victory over the Rebels (CSA)
The Battle of Gettysburg Place where the battle was fought: Gettysburg, Pennsylvania.
On July 3rd 1863!
High Casualties, Many soldiers retreating, and Confederate Victory.
The Union victory at Gettysburg prevented the Confederate armies from continuing their attack into Northern territories. The Union victory at Vicksburg allowed the Union Navy to use the river to sail deep into Confederate territories.
The Union victory effectively stopped Lee's invasion of the North.
General George Meade
That was Gettysburg. The Union victory on the 3rd came at the same moment as the other Union victory, far away on the Mississippi at Vicksburg.
Gettysburg was THE key victory for the Union. Vicksburg gave the Union control of the Mississippi, and divided the Confederacy in two.