The Rockville Expedition

On the 8th, General-in-Chief Winfield Scott directed Colonel Charles P. Stone to march northwest from Washington, guard the upper Potomac River against Confederates, stop the transport of Confederate supplies from Baltimore to Virginia, open the Chesapeake & Ohio Canal which was blocked near Leesburg, and “give countenance to our friends in Maryland and Virginia.” Stone was also ordered to communicate with Major General Robert Patterson, who was about to move out of Pennsylvania toward Harpers Ferry, and if possible, join forces with him.

Stone’s force consisted of his 14th U.S. Infantry along with two infantry regiments, four infantry battalions, two cavalry companies, and two cannon from the District of Columbia militia. These 2,500 men moved out on the 10th, advancing up the Maryland side of the Potomac to Edwards’s Ferry at Tennallytown. They entered Rockville the next day, where Stone set up headquarters and deployed several detachments to nearby towns along the river. This caused anxiety among Confederates as far west as Harpers Ferry.

Confederate forces crossed the Potomac on the morning of the 12th and tried to damage the Chesapeake & Ohio Canal at Edwards’s Ferry. They returned to Virginia after the lock-keeper drained the water and convinced them that it was broken. Meanwhile, Stone used both the C&O Canal and local roads to move his Federals from Rockville to Seneca Creek, Seneca Mills, Darnestown, Tennallytown, and Edwards’s Ferry.

Skirmishing occurred between Confederates and Stone’s men at Seneca Falls on the 14th. The Federals also operated at Great Falls and Darnestown while securing the C&O Canal as far north as Edwards’s Ferry and protecting the property of local Unionists. Federal engineers removed a 100-ton boulder from the Baltimore & Ohio Railroad tracks at Point of Rocks, which Confederates had somehow rolled there to block the line. Warned to “look out for squalls” from Confederates supposedly operating at Edwards’s Ferry, Stone deployed a regiment toward Poolesville and advanced with his cavalry to investigate the ferry.

The Federals seized both Edwards’s and Conrad’s ferries on the 15th before Stone got word that a Confederate force of unknown size was advancing from Leesburg to confront him. From Poolesville, between the ferries, Stone reported that Confederates around Leesburg were firing artillery rounds across the Potomac at his troops guarding Conrad’s Ferry. Stone awaited official word that Confederates had abandoned Harpers Ferry while his cannon prevented Confederates from crossing the river at Edwards’s Ferry. He planned to fall back to Washington if the Confederates had not evacuated Harpers Ferry, but if they did, he planned to move on Leesburg.

Stone reported that a Confederate deserter had assured him that residents of Martinsburg who had been forced into Confederate military service were “strong Union men, who are determined to shoot their officers and go over to the Government troops the first opportunity.” Stone sent scouts to Harpers Ferry, who reported it destroyed and abandoned, but they did not report seeing any Federal troops or sympathizers. This indicated that General Patterson’s forces had not yet occupied Harpers Ferry.

On the 21st, General-in-Chief Scott directed Patterson to absorb Stone’s Federals and move on Maryland Heights, overlooking Harpers Ferry. Patterson was also to clear Confederates out of Leesburg while seizing all the fords and ferries in the area. Scott envisioned a two-pronged advance into Virginia by Patterson from the Shenandoah Valley and Major General Irvin McDowell from Washington. Patterson moved slowly due to false rumors that Confederates might have retaken Harpers Ferry.

The next day, Scott informed Stone that he “would be glad that you should furnish him any suggestions that may occur to you,” even though Stone’s small Federal force would soon be absorbed into Patterson’s larger army. Stone reported that he had sent troops as far north as the mouth of the Monocacy River and eight miles north of Point of Rocks, but no Confederates were found. Stone requested more artillery so he could occupy Leesburg for Patterson.

On Sunday the 30th, Scott ordered Stone to join forces with Patterson near Martinsburg, northwest of Harpers Ferry. Stone’s Federals had been positioned at Poolesville, between Edwards’s and Conrad’s ferries. Both Patterson and Stone moved with extreme care as June ended because they did not have accurate intelligence on the size of the Confederate force at Leesburg.


  • Long, E.B. with Long, Barbara, The Civil War Day by Day. New York: Da Capo Press, Inc., 1971.
  • Longacre, Edward G. (Patricia L. Faust ed.), Historical Times Illustrated Encyclopedia of the Civil War. New York: Harper & Row, 1986.

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