What was the battle of Gettysburg most known for?

Answer 1

It stopped Lee's invasion of the north, and the valiant but fruitless charge commanded by George Pickett on day three of the battle.

But there were other things. Meade had recently been put in command of the Army of the Potomac, and many felt Lee would be too much for him, as Lee consistently had proven himself superior to his adversaries.

Lee's subordinates failed him at Gettysburg. Stuart was riding around the Union army, and took longer than expected, and did not show til day two. This caused Lee's army to blunder into a fight unexpectedly. Also, Longstreet was sullen and balky, because Lee refused his advice to move the army to the right, and interpose the rebel army between the Union forces and the cities of Baltimore and Washington.

General Ewell was slow getting an attack ready for the taking of Little Round Top as ordered and the Union forces occupied it.

There seems little doubt if Jackson had not died at Chancellorsville, he would certainly have taken Little Round Top, and possibly won the battle and even the war.