The loyalty of Maryland to the Union was more than doubtful.  As a slave-holding State, her sympathies were strongly Southern; and it was only her geographical situation, north of the Potomac, and with no strong frontier to protect her from invasion, which had held her back from joining the Confederacy.  As only a single line of railway connected Washington with the North, passing through Baltimore, the chief city of Maryland, a very hot-bed of secession sentiment, the attitude of the State was a matter of the utmost anxiety to the Federal Government.  An attempt to send troops through Baltimore to Washington had provoked a popular commotion and some bloodshed.  Stern measures had been necessary to keep the railway open.  Baltimore was placed under martial law, and strongly garrisoned.  But despite these precautions, for some weeks the feeling in Maryland was so hostile to the Union that it was not considered safe for the Northern troops to cross her territory except in large numbers; and the concentration at Washington of a force sufficient to defend it was thus attended with much difficulty.

A single railroad, too, the Baltimore and Ohio, connected Washington with the West.  Crossing the Potomac at Harper’s Ferry, and following the course of the river, it ran for one hundred and twenty miles within the confines of Virginia.  Thus the district commanded by Jackson embraced an artery of supply and communication which was of great importance to the enemy.  The natural course would have been to destroy the line at once; but the susceptibilities of both Maryland and West Virginia had to be considered.  The stoppage of all traffic on their main trade route would have done much to alienate the people from the South, and there was still hope that Maryland might throw in her lot with her seceded sisters.

The line was therefore left intact, and the company was permitted to maintain the regular service of trains, including the mails.  For this privilege, however, Jackson exacted toll.  The Confederate railways were deficient in rolling stock, and he determined to effect a large transfer from the Baltimore and Ohio.  From Point of Rocks, twelve miles east of Harper’s Ferry, to Martinsburg, fifteen miles west, the line was double.  “The coal traffic along it,” says General Imboden, “was immense, for the Washington Government was accumulating supplies of coal on the seaboard.  These coal trains passed Harper’s Ferry at all hours of the day and night, and thus furnished Jackson with a pretext for arranging a brilliant capture.  A detachment was posted at Point of Rocks, and the 5th Virginia Infantry at Martinsburg.  He then complained to the President of the Baltimore and Ohio that the night trains, eastward bound, disturbed the repose of his camp, and requested a change of schedule that would pass all east-bound trains by Harper’s Ferry between eleven and one o’clock in the daytime.  The request was complied with, and thereafter for