General Heth quoted.
On the morning of June 29th General Lee ordered a concentration of the army at Cashtown, a village at the eastern base of the mountain, Hill's Corps was in advance; he reached Cashtown June 30th. That night Hill and Heth heard that there was a force of the enemy at Gettysburg; early the next morning Hill, without orders, with Heth's and Pender's Divisions, started down the Gettysburg 'pike. General Lee was then west of the mountain with Longstreet. Buford's Cavalry was holding Gettysburg as an outpost. Heth was in advance, and soon ran against Buford. There was a pretty stiff fight with the cavalry until Reynolds, who was camped some six miles back, came to his support. Heth says: [352]‘Archer and Davis were now directed to advance, the object being to feel the enemy; to make a forced reconnoissance, and determine in what force the enemy were—whether or not he was moving his forces on Gettysburg. Heavy columns of the enemy were soon encountered.’
Davis's and Archer's Brigades were soon smashed, and Archer, with a good many of his men, made prisoners. ‘The enemy,’ says General Heth, ‘had now been felt and found to be in heavy force. The division was now formed in line of battle,’ etc.
The object of a reconnoissance is to get information; after getting the information the attacking force retires. It seems that General Heth ought now to have been satisfied that the enemy was in force, and should have returned to Cashtown—i. e., if he only went to make a reconnoissance. Hill now put in Pender's and Heth's divisions, and says they drove the enemy until they came upon the First and Eleventh corps that Reynolds had brought up. He says that he went to Gettysburg ‘to find out what was in my front.’ He had now found it. Hill would have been driven back to Cashtown if Ewell had not come to his support. With Rodes's and Early's divisions, he had camped the night before a few miles north of Gettysburg, and had started to Cashtown when he received a note from Hill telling him he was moving to Gettysburg. The battle had then begun. Ewell, not understanding Hill's object in going to Gettysburg, hearing the sound of battle, and no doubt supposing the army was assembling there, turned the head of his column and marched toward Gettysburg. He came up just in time to save Hill.