[Vigilanteman]

Don't forget that Confederate cavalry made it to the outskirts of Washington, DC during the Monocacy campaign later in 1864. The real beginning of the end didn't really come until Petersburg fell and, with it, the defensive perimeter for Richmond in February 1865.

Historians today recognize Gettysburg as the turning point. Back then, it was seen as just another major battle.

[Bull Snipe]

More than cavalry. Early approached Washington D.C. with an army of nearly 10,000 men.

While Gettysburg was the largest battle of the war. It’s main accomplishment was break the offensive power of the Army of Northern Virginia. Lee lost about one third of his army as casualties. For the rest of the War, the ANV was pretty much limited to going wherever the Army of the Potomac wanted to go.
Whether it was the turning point of the war is debatable. Some think McClellan’s drawn battle at Antietam had more impact on the outcome of the war than Gettysburg. The reason is that it was just enough of a win for Lincoln to issue the Emancipation Proclamation. That event made European intervention, on the side of the Confederacy, very unlikely. Without direct European intervention, the prospect of the Confederacy winning the war declined drastically.