Between September 4th and 7th, 1862, the Army of Northern Virginia, General Robert E. Lee, Commanding, crossed the Potomac near Leesburg, and occupied Frederick, Maryland. On the 10th a movement was made to surround and capture the Union forces at Harpers Ferry. Early that morning General T. J. Jackson with Jackson's (Stonewall) Division and the Divisions of R. S. Ewell. and A. P. Hill left Frederick, marched over South Mountain at Turner's Pass, six miles north of this, crossed the Potomac near Williamsport on the 11th, seized Martinsburg on the 12th and marching by way of Charlestown on the 13th invested Harpers Ferry from the Virginia side of the Potomac. General Lee with the Division of D. R. Jones and J. B. Hood and the Brigade of N. G. Evans, marched to Hagerstown. D. H. Hill's Division halted at Boonsboro to prevent the escape of the garrison at Harpers Ferry through Pleasant Valley and to support Stuart's Cavalry which remained east of South Mountain to observe the movements of the Union Army and retard its advance. McLaws with his own Division and that of R. H. Anderson moved from Frederick on the 10th, in rear of D. H. Hill, left the Frederick and Hagerstown Pike at Middletown, crossed South Mountain at Brownsville Pass, one mile south of this and bivouacked near Brownsville on the night of the 11th. On the 12th McLaws marched onto Maryland Heights and down Pleasant Valley to invest Harpers Ferry from the Maryland side of the Potomac, leaving Semmes' Brigade to hold Brownsville Pass. Mahone's at Brownsville and Munford's Cavalry in front of Crampton's Pass to guard his rear and observe the movements of the Union Army.