"Jackson" sailed with Hollins' squadron to attack five of the Federal blockaders at the Head of Passes, Mississippi River, on 12 October 1861. They successfully routed the Union forces and proceeded to the defense of Forts Jackson and St. Philip which the United States Mortar Flotilla under Commodore David Dixon Porter bombarded from 18 to 24 April 1862. On 23 April "Jackson" was despatched to make the canals above the fort inaccessible to Union ships.