The Copperhead movement in the Northern states was a broad group of anti-war democrats, Southern sympathizers, Union Army deserters, and Lincoln-haters, and the densest concentrations of Copperheads were along the southern halves of Ohio, Indiana, and Illinois.
Rear Admiral John Dahlgren had known that the vast British fleet would soon arrive to drive off the Union Blockade of the Confederacy, and so he had set about concentrating as many ships as possible inside of the sandbar off Charleston.