Lee’s order of June 23rd to Stuart says that in exercise of the discretion given him (Stuart) would pass around the rear of the Federal army with three brigades and cross the Potomac between it and Washington. Both Lee and Stuart believed that Stuart would be able, by this route, to place himself on the Confederate right flank and to keep Lee properly advised on the enemy’s movement. Lee set Stuart's final destination as York, PA where he would join up with General Early.
On June 24th, Stuart, along with the brigades of Wade Hampton, Fitz Lee, and Rooney Lee (under the command of Colonel Chambliss) began their movements. Stuart left Robertson’s and Jones’ brigades to provide a screen for the army, to protect the passes, and to be the “eyes and ears” of Lee’s army. This gave Lee over 3,000 cavalry members to accompany him into Pennsylvania. 3,800 cavalry members went with Stuart.
By the night of the 24th, Stuart found Hancock’s Corp, marching northward, and occupying the road that Stuart had planned to use. After a brief skirmish, Stuart captured some prisoners, interrogated them, and discovered that Hancock was moving north in the “great pursuit.”
Stuart sent word to Lee, by courier, that the Union Army was now in pursuit. This courier was captured.
Stuart’s original plan was now in disarray. He decided to continue his mission by taking an alternative route. To swing wide of Hancock’s Corp, Stuart had to retreat 60 miles. Of course, hindsight being perfect, Stuart had a wide-open route to Gettysburg. But, let’s be honest. Gettysburg wasn’t Stuart’s objective. Stuart expected to find Early not in Gettysburg, but in York.
Stuart did his job very well. He was to distract the Yankees from knowing where the Confederate Army was headed. Among the direct results of Stuart’s movements was that Meade was deprived of the services of all his cavalry units except Buford’s division until noon on July 2nd. And on the 2nd day of battle, Buford’s division was withdrawn to protect the supply wagons because Meade knew that Stuart was behind him. This left the Sickles’ flank unguarded. The failure to roll up Sickles’ flank cannot be attributed to Stuart.
A portion of French’s command was diverted eastward to protect communication with Washington. If you read the dispatches between Meade and Hillock from June 28th to July 1st, they were confused to where Lee was. They could not figure out why Stuart was so far east. Meade dispatched his largest Corp – the 6th - to guard against Stuart’s sudden advance.
What is strange is why Lee did not use Robertson and Jones for the purposes of scouting. In the daily communication between Lee and Robertson, Lee asks nothing from Robertson. It wasn’t until July 1st that Robertson was summoned. Yet, Lee knew exactly where Robertson was. Robertson had 3,000 men. If Lee was really concerned about being blind in enemy territory, he had 6,000 pair of eyes idling at Berryville.
Let’s be clear… It was not the want of cavalry that General Lee bewailed, for he enough of it had it been properly used. It was the absence of Stuart himself that he felt so keenly; for on Stuart had Lee learned to rely to such an extent that it seemed as if his cavalry were concentrated in Stuart’s person, and from Stuart alone could information be expected.