On September 9, part of the Army of Northern Virginia's artillery under Colonel R. L. Walker escorted by Col. Elijah V. White's Battalion entered Loudoun county at Point of Rocks after unsuccessfully trying to destroy the C&O Canal aqueduct over the Monocacy River. White led Walker to Loudoun Heights by way of Lovettsville and Hillsboro, as part of Robert E. Lee's plan to take Harpers Ferry to protect his flank during his Maryland Campaign.