The key outcome of the Battle of Gettysburg was a decisive victory for the Union forces, marking a turning point in the American Civil War. The battle, fought from July 1 to July 3, 1863, resulted in significant casualties for both sides, with the Union army repelling Confederate General Robert E. Lee's invasion of the North. Subsequently, this victory bolstered Union morale and diminished the South's capability to wage offensive war. It also set the stage for President Lincoln's famous Gettysburg Address, which redefined the purpose of the war and emphasized the principles of liberty and equality.