Headquarters Army of Northern Virginia, Sharpsburg, MD, September 18, 1862. Mr. President:
On the afternoon of the 16th instant the enemy, who, you were informed on that day, was in our front, opened a light fire of artillery upon our line. Early next morning it was renewed in earnest, and large masses of the Federal troops that had crossed the Antietam above our position assembled on our left and threatened to overwhelm us.
They advanced in three compact lines. The divisions of Generals McLaws, R. H. Anderson, A. P. Hill, and Walker had not arrived the previous night, as I had hoped, and were still beyond the Potomac. Generals Jackson's and Ewell's divisions were thrown to the left of Generals D. H. Hill and Longstreet. The enemy advanced between the Antietam and the Sharpsburg and Hagerstown turnpike, and was met by General Hill's and the left of General Longstreet's division, where the contest raged fiercely, extending to our entire left.. The enemy was driven back and held in check, but before the divisions of McLaws, Anderson, and Walker - who, upon their arrival on the morning of the 17th, were advanced to support the left wing and center - could be brought into action, that portion of our lines was forced back by superior numbers. The line, after a severe conflict, was restored and the enemy driven back, and our position maintained during the rest of the day.
In the afternoon the enemy advanced on our right, where General Jones' division was posted, who handsomely maintained his position. General Toombs' brigade, guarding the bridge over Antietam Creek, gallantly resisted the approach of the enemy; but his superior numbers enabling him to extend his left, he crossed below the bridge, and assumed a threatening attitude on our right., which fell back in confusion. By this time, between 3 and 4 p.m., General A. P. Hill, with five of his brigades, reached the scene of action, drove the enemy immediately from the position they had taken, and continued the contest until dark, restoring our right and maintaining our ground.
R. E. Lee,
His Excellency President Davis
Note: by General Robert E. Lee