After the First Manassas victory, the Confederate army established a defensive line from Centreville along the Occoquan River to the Potomac River. In October, the Confederates constructed batteries at Evansport, Freestone Point, Shipping Point, and Cockpit Point to close the Potomac River to shipping and isolate Washington. The Blockade of the Potomac River Campaign lasted from October 1861 to January 1862. By mid-December, the Confederates had 37 heavy guns in position along the river.
Cockpit Point – (January 3, 1862) – Also called the Battle of Freestone Point or the Battle of Shipping Point, this attack took place in Prince William County, Virginia. On January 3, Cockpit Point was shelled by the Anacostia and Yankee, with neither side gaining an advantage. Union ships approached the point again on March 9 but discovered that the Confederates had abandoned their works and retired closer to Richmond, after effectively sealing off the Potomac River for nearly five months. The number of casualties in the inconclusive battle is unknown.