As soon as it was known that Lee was on the way, the people of Pennsylvania felt what the consequence could be, and feared what it might be. The State was divided into two Military Districts. The Department of the Monongahela, west of the Laurel Ridge Mountains, was commanded by General Brooks, Headquarters, Pittsburg; and the Department of the Susquehanna by General Couch, Headquarters, Chambersburg.
On June 14th, Milroy was forced out of Winchester, leaving behind siege guns, 8 field pieces, 6000 muskets, ammunition and stores.
June 15th, the President called on Maryland and West Virginia for 10,000 militia, each; Ohio for 30,000, and Pennsylvania for 50,000, for six months' service.
June 16th, Jenkins' rebel cavalry, 950 strong, occupied Chambersburg, and withdrew on the 18th.
19th, portion of Rhodes' rebel cavalry entered McConnelsburg and sacked the town.
21st, Pleasanton drove Stuart beyond Middletown, through Upperville and Ashby's Gap.
23d, rebel forces again occupied Chambersburg, the Union troops in the town falling back.
26th, rebel advance reached Carlisle, the militia under General Knipe retiring.
Lee's forces were well under way down the Valley, when Hooker took down his tents opposite Fredericksburg.