Second Army Corps

   Richardson's Division of the Second Corps, in close pursuit of the Army of Northern Virginia in its retreat from South Mountain, passed through Boonsboro and Keedysville on the morning of September 15th, and, early in the afternoon, took position behind the bluff bordering the Antietam west of this, the skirmishers of the Division being advanced onto the bluff and engaging those of the enemy behind the creek. French's Division followed later in the day and went into bivouac on either side of the road at this point. Sedgwick's Division bivouacked on French's right, its right east of the Pry house. The three divisions remained in these positions until the morning of the 17th when they crossed the Antietam at Pry's Ford and went into action on the right and right center of the Union line.