Numbers 75. Itinerary of the Department of the Susquehanna, July 3-August 1.*
July 3.-Four pieces of artillery and one company of infantry moved from Harrisburg, McLean's detachment of cavalry from Carlisle Barracks, and 150 infantry from draft rendezvous, Carlisle, to resist the enemy's advance into Cumberland Valley, which was at Martinsburg at that time.
July 5.-Lieutenant McLean's command sent to Hagerstown.
July 6.-Lieutenant McLean's force driven out of Hagerstown by McCausland's command, losing 1 non-commissioned officer and 4 men.
July 7.-Headquarters Department of the Susquehanna moved to Harrisburg.
July 8.-Brigadier General Thomas A. Rowley, U. S. Volunteers, placed in command of U. S. forces in vicinity of Chambersburg.
July 10.-At 4 p. m. Major General George Cadwalader, at Philadelphia, directed to send 200 men and two pieces of artillery to guard the bridges across Gunpowder Creek, on the Philadelphia and Baltimore Railroad, in the Middle Department.
July 12.-Sent one company of cavalry from Lehigh District, 100 infantry from Chambersburg, and 200 convalescents from York to Hanover Junction, on the Northern Central Railroad.
July 18.-Captain R. M. Evans, with his mounted Philadelphia Scouts, sent to Emmitsburg.
July 22.-Captain E. B. Sanno's mounted company, 100-days' Pennsylvania volunteers, sent to Waynesborough, and Captain George D. Stroud's mounted 100-days' Pennsylvania volunteers, to Shimpstown.
July 24.-Sent two regiments 100-days' Pennsylvania volunteers to report to Major-General Wallace, commanding Middle Department.
July 25.-Changed headquarters of this department from Harrisburg to Chambersburg.
July 26.-One regiment 100-days' Pennsylvania volunteers, sent from Pittsburg to Baltimore, to report to Major-General Wallace, commanding Middle Department.
July 27.-Lieutenant H. T. McLean's detachment U. S. cavalry (forty-five men) arrived from Carlisle Barracks and sent to Shimpstown, near Mercersburg. Captains Sanno and Stroud ordered to report with their commands to Brigadier-General Averell, at Hagerstown.
July 28.-In obedience to orders from Major-General Halleck, chief of staff, ordered six companies 100-days' Pennsylvania volunteers to report to General Averell, at Hagerstown.
July 29.-Forces in Chambersburg consisted of Captain Thomas S. McGowan's company Maryland Volunteers (sixty men), and one section Battery A, First New York Light Artillery. At 10 a. m. the enemy, consisting of McCausland's and Bradley T. Johnson's brigades of cavalry, about 2,600 strong, and six pieces of artillery, commenced crossing the Potomac River at McCoy's Ferry. At 5 p. m. McLean's forces driven out of Mercersburg; 11 p. m. attacked his pickets at Bridgeport; enemy marched steadily on to Saint Thomas, and from there on the London turnpike in direction of Chambersburg, until they arrived within one mile of the town.
* From monthly returns.